song global volume and mixer volume

Implemented in it2taud.py:
- _parse_it_pf_envelope_raw() (it2taud.py:677) — parses IT's third envelope at IMPI+0x1D4, keeping all 25 nodes (no decimation), distinguishing pitch vs filter mode via flag bit 7.
- _env_value_at() — tick-time linear interpolation honouring env-loop wrap.
- _clone_sample(), _plan_baked_length() — sample copy and entry + N×loop_len length planner (N up to 16).
- _bake_pitch_envelope() — time-varying linear-interpolated resampling, rate = 2^(env_v/12).
- _bake_filter_envelope() — RBJ 2-pole resonant LP biquad with time-varying coefficients; cutoff mapped 110 Hz (env_v=−32) → ~28 kHz (env_v=+32), Q from inst.ifr ∈ [0.5, 6.0].
- ITInstrument extended with pf_nodes, pf_flags, ifc, ifr. parse_instruments() reads IFC/IFR at IMPI+0x39/0x3A and pf envelope at IMPI+0x1D4.
- assemble_taud() use_instruments branch now substitutes baked copies in the proxy[] list (originals in samples[] stay intact).
- --no-pf-envelope CLI flag for A/B testing; module docstring updated.

.gitignore

@@ -66,3 +66,7 @@ assets/disk0/home/basic/*
 assets/disk0/movtestimg/*.jpg
 assets/disk0/*.mov
 assets/diskMediabin/*
+
+video_encoder/*
+
+assets/disk0/tvdos/bin/tautfont.png

.idea/artifacts/TerranBASIC.xml

@@ -21,36 +21,54 @@
       <element id="extracted-dir" path="$MAVEN_REPOSITORY$/org/jetbrains/kotlin/kotlin-reflect/1.8.21/kotlin-reflect-1.8.21.jar" path-in-jar="/" />
       <element id="extracted-dir" path="$MAVEN_REPOSITORY$/org/jetbrains/kotlin/kotlin-test/1.8.21/kotlin-test-1.8.21.jar" path-in-jar="/" />
       <element id="extracted-dir" path="$MAVEN_REPOSITORY$/org/jetbrains/kotlin/kotlin-stdlib-common/1.8.21/kotlin-stdlib-common-1.8.21.jar" path-in-jar="/" />
-      <element id="extracted-dir" path="$PROJECT_DIR$/lib/graal-sdk-22.3.1.jar" path-in-jar="/" />
-      <element id="extracted-dir" path="$PROJECT_DIR$/lib/icu4j-71.1.jar" path-in-jar="/" />
-      <element id="extracted-dir" path="$PROJECT_DIR$/lib/js-22.3.1-edit.jar" path-in-jar="/" />
-      <element id="extracted-dir" path="$PROJECT_DIR$/lib/js-scriptengine-22.3.1.jar" path-in-jar="/" />
-      <element id="extracted-dir" path="$PROJECT_DIR$/lib/regex-22.3.1-edit.jar" path-in-jar="/" />
-      <element id="extracted-dir" path="$PROJECT_DIR$/lib/truffle-api-22.3.1.jar" path-in-jar="/" />
+      <element id="extracted-dir" path="$PROJECT_DIR$/lib/polyglot-23.1.10.jar" path-in-jar="/" />
+      <element id="extracted-dir" path="$PROJECT_DIR$/lib/js-language-23.1.10.jar" path-in-jar="/" />
+      <element id="extracted-dir" path="$PROJECT_DIR$/lib/js-scriptengine-23.1.10.jar" path-in-jar="/" />
+      <element id="extracted-dir" path="$PROJECT_DIR$/lib/truffle-api-23.1.10.jar" path-in-jar="/" />
+      <element id="extracted-dir" path="$PROJECT_DIR$/lib/truffle-runtime-23.1.10.jar" path-in-jar="/" />
+      <element id="extracted-dir" path="$PROJECT_DIR$/lib/truffle-compiler-23.1.10.jar" path-in-jar="/" />
+      <element id="extracted-dir" path="$PROJECT_DIR$/lib/compiler-23.1.10.jar" path-in-jar="/" />
+      <element id="extracted-dir" path="$PROJECT_DIR$/lib/compiler-management-23.1.10.jar" path-in-jar="/" />
+      <element id="extracted-dir" path="$PROJECT_DIR$/lib/word-23.1.10.jar" path-in-jar="/" />
+      <element id="extracted-dir" path="$PROJECT_DIR$/lib/regex-23.1.10.jar" path-in-jar="/" />
+      <element id="extracted-dir" path="$PROJECT_DIR$/lib/icu4j-23.1.10.jar" path-in-jar="/" />
+      <element id="extracted-dir" path="$PROJECT_DIR$/lib/collections-23.1.10.jar" path-in-jar="/" />
+      <element id="extracted-dir" path="$PROJECT_DIR$/lib/nativeimage-23.1.10.jar" path-in-jar="/" />
+      <element id="extracted-dir" path="$PROJECT_DIR$/lib/jniutils-23.1.10.jar" path-in-jar="/" />
       <element id="extracted-dir" path="$PROJECT_DIR$/lib/gdx-1.12.1.jar" path-in-jar="/" />
       <element id="extracted-dir" path="$PROJECT_DIR$/lib/lwjgl-3.3.3.jar" path-in-jar="/" />
       <element id="extracted-dir" path="$PROJECT_DIR$/lib/lwjgl-stb-3.3.3.jar" path-in-jar="/" />
       <element id="extracted-dir" path="$PROJECT_DIR$/lib/lwjgl-glfw-3.3.3.jar" path-in-jar="/" />
-      <element id="extracted-dir" path="$PROJECT_DIR$/lib/js-22.3.1-javadoc.jar" path-in-jar="/" />
-      <element id="extracted-dir" path="$PROJECT_DIR$/lib/js-22.3.1-sources.jar" path-in-jar="/" />
+      <element id="extracted-dir" path="$PROJECT_DIR$/lib/js-language-23.1.10-javadoc.jar" path-in-jar="/" />
+      <element id="extracted-dir" path="$PROJECT_DIR$/lib/js-language-23.1.10-sources.jar" path-in-jar="/" />
       <element id="extracted-dir" path="$PROJECT_DIR$/lib/gdx-1.12.1-javadoc.jar" path-in-jar="/" />
       <element id="extracted-dir" path="$PROJECT_DIR$/lib/gdx-1.12.1-sources.jar" path-in-jar="/" />
-      <element id="extracted-dir" path="$PROJECT_DIR$/lib/icu4j-71.1-javadoc.jar" path-in-jar="/" />
-      <element id="extracted-dir" path="$PROJECT_DIR$/lib/icu4j-71.1-sources.jar" path-in-jar="/" />
+      <element id="extracted-dir" path="$PROJECT_DIR$/lib/icu4j-23.1.10-javadoc.jar" path-in-jar="/" />
+      <element id="extracted-dir" path="$PROJECT_DIR$/lib/icu4j-23.1.10-sources.jar" path-in-jar="/" />
       <element id="extracted-dir" path="$PROJECT_DIR$/lib/lwjgl-openal-3.3.3.jar" path-in-jar="/" />
       <element id="extracted-dir" path="$PROJECT_DIR$/lib/lwjgl-opengl-3.3.3.jar" path-in-jar="/" />
       <element id="extracted-dir" path="$PROJECT_DIR$/lib/lwjgl-3.3.3-javadoc.jar" path-in-jar="/" />
       <element id="extracted-dir" path="$PROJECT_DIR$/lib/lwjgl-3.3.3-sources.jar" path-in-jar="/" />
       <element id="extracted-dir" path="$PROJECT_DIR$/lib/lwjgl-jemalloc-3.3.3.jar" path-in-jar="/" />
-      <element id="extracted-dir" path="$PROJECT_DIR$/lib/regex-22.3.1-javadoc.jar" path-in-jar="/" />
-      <element id="extracted-dir" path="$PROJECT_DIR$/lib/regex-22.3.1-sources.jar" path-in-jar="/" />
+      <element id="extracted-dir" path="$PROJECT_DIR$/lib/regex-23.1.10-javadoc.jar" path-in-jar="/" />
+      <element id="extracted-dir" path="$PROJECT_DIR$/lib/regex-23.1.10-sources.jar" path-in-jar="/" />
       <element id="extracted-dir" path="$PROJECT_DIR$/lib/TerranVirtualDisk-src.jar" path-in-jar="/" />
       <element id="extracted-dir" path="$PROJECT_DIR$/lib/jorbis-0.0.17-javadoc.jar" path-in-jar="/" />
       <element id="extracted-dir" path="$PROJECT_DIR$/lib/jorbis-0.0.17-sources.jar" path-in-jar="/" />
       <element id="extracted-dir" path="$PROJECT_DIR$/lib/lwjgl-stb-3.3.3-javadoc.jar" path-in-jar="/" />
       <element id="extracted-dir" path="$PROJECT_DIR$/lib/lwjgl-stb-3.3.3-sources.jar" path-in-jar="/" />
-      <element id="extracted-dir" path="$PROJECT_DIR$/lib/graal-sdk-22.3.1-javadoc.jar" path-in-jar="/" />
-      <element id="extracted-dir" path="$PROJECT_DIR$/lib/graal-sdk-22.3.1-sources.jar" path-in-jar="/" />
+      <element id="extracted-dir" path="$PROJECT_DIR$/lib/polyglot-23.1.10-javadoc.jar" path-in-jar="/" />
+      <element id="extracted-dir" path="$PROJECT_DIR$/lib/polyglot-23.1.10-sources.jar" path-in-jar="/" />
+      <element id="extracted-dir" path="$PROJECT_DIR$/lib/truffle-api-23.1.10-javadoc.jar" path-in-jar="/" />
+      <element id="extracted-dir" path="$PROJECT_DIR$/lib/truffle-api-23.1.10-sources.jar" path-in-jar="/" />
+      <element id="extracted-dir" path="$PROJECT_DIR$/lib/truffle-runtime-23.1.10-javadoc.jar" path-in-jar="/" />
+      <element id="extracted-dir" path="$PROJECT_DIR$/lib/truffle-runtime-23.1.10-sources.jar" path-in-jar="/" />
+      <element id="extracted-dir" path="$PROJECT_DIR$/lib/collections-23.1.10-javadoc.jar" path-in-jar="/" />
+      <element id="extracted-dir" path="$PROJECT_DIR$/lib/collections-23.1.10-sources.jar" path-in-jar="/" />
+      <element id="extracted-dir" path="$PROJECT_DIR$/lib/nativeimage-23.1.10-javadoc.jar" path-in-jar="/" />
+      <element id="extracted-dir" path="$PROJECT_DIR$/lib/nativeimage-23.1.10-sources.jar" path-in-jar="/" />
+      <element id="extracted-dir" path="$PROJECT_DIR$/lib/jniutils-23.1.10-javadoc.jar" path-in-jar="/" />
+      <element id="extracted-dir" path="$PROJECT_DIR$/lib/jniutils-23.1.10-sources.jar" path-in-jar="/" />
       <element id="extracted-dir" path="$PROJECT_DIR$/lib/jlayer-1.0.1-gdx-javadoc.jar" path-in-jar="/" />
       <element id="extracted-dir" path="$PROJECT_DIR$/lib/jlayer-1.0.1-gdx-sources.jar" path-in-jar="/" />
       <element id="extracted-dir" path="$PROJECT_DIR$/lib/lwjgl-glfw-3.3.3-javadoc.jar" path-in-jar="/" />
@@ -62,15 +80,15 @@
       <element id="extracted-dir" path="$PROJECT_DIR$/lib/lwjgl-openal-3.3.3-sources.jar" path-in-jar="/" />
       <element id="extracted-dir" path="$PROJECT_DIR$/lib/lwjgl-opengl-3.3.3-javadoc.jar" path-in-jar="/" />
       <element id="extracted-dir" path="$PROJECT_DIR$/lib/lwjgl-opengl-3.3.3-sources.jar" path-in-jar="/" />
-      <element id="extracted-dir" path="$PROJECT_DIR$/lib/truffle-api-22.3.1-javadoc.jar" path-in-jar="/" />
-      <element id="extracted-dir" path="$PROJECT_DIR$/lib/truffle-api-22.3.1-sources.jar" path-in-jar="/" />
+      <element id="extracted-dir" path="$PROJECT_DIR$/lib/regex-23.1.10-javadoc.jar" path-in-jar="/" />
+      <element id="extracted-dir" path="$PROJECT_DIR$/lib/regex-23.1.10-sources.jar" path-in-jar="/" />
       <element id="extracted-dir" path="$PROJECT_DIR$/lib/lwjgl-3.3.3-natives-windows.jar" path-in-jar="/" />
       <element id="extracted-dir" path="$PROJECT_DIR$/lib/lwjgl-jemalloc-3.3.3-javadoc.jar" path-in-jar="/" />
       <element id="extracted-dir" path="$PROJECT_DIR$/lib/lwjgl-jemalloc-3.3.3-sources.jar" path-in-jar="/" />
       <element id="extracted-dir" path="$PROJECT_DIR$/lib/lwjgl-stb-3.3.3-natives-linux.jar" path-in-jar="/" />
       <element id="extracted-dir" path="$PROJECT_DIR$/lib/lwjgl-stb-3.3.3-natives-macos.jar" path-in-jar="/" />
-      <element id="extracted-dir" path="$PROJECT_DIR$/lib/js-scriptengine-22.3.1-javadoc.jar" path-in-jar="/" />
-      <element id="extracted-dir" path="$PROJECT_DIR$/lib/js-scriptengine-22.3.1-sources.jar" path-in-jar="/" />
+      <element id="extracted-dir" path="$PROJECT_DIR$/lib/js-scriptengine-23.1.10-javadoc.jar" path-in-jar="/" />
+      <element id="extracted-dir" path="$PROJECT_DIR$/lib/js-scriptengine-23.1.10-sources.jar" path-in-jar="/" />
       <element id="extracted-dir" path="$PROJECT_DIR$/lib/lwjgl-glfw-3.3.3-natives-linux.jar" path-in-jar="/" />
       <element id="extracted-dir" path="$PROJECT_DIR$/lib/lwjgl-glfw-3.3.3-natives-macos.jar" path-in-jar="/" />
       <element id="extracted-dir" path="$PROJECT_DIR$/lib/gdx-jnigen-loader-2.3.1-javadoc.jar" path-in-jar="/" />

.idea/cody_history.xml

@@ -0,0 +1,133 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ChatHistory">
+    <accountData>
+      <list>
+        <AccountData>
+          <accountId value="VXNlcjo1NTUxMzY=" />
+          <chats>
+            <list>
+              <chat>
+                <internalId value="8a32c880-d8ec-4d84-b5f7-a62b2edf63c3" />
+                <llm>
+                  <llm>
+                    <model value="anthropic/claude-3-5-sonnet-20240620" />
+                    <provider value="Anthropic" />
+                    <title value="Claude 3.5 Sonnet" />
+                    <usage>
+                      <list>
+                        <option value="chat" />
+                        <option value="edit" />
+                      </list>
+                    </usage>
+                  </llm>
+                </llm>
+              </chat>
+              <chat>
+                <internalId value="f4e7338b-57d3-44e0-b1d9-04aa2dfb4bae" />
+                <llm>
+                  <llm>
+                    <model value="anthropic/claude-3-5-sonnet-20240620" />
+                    <provider value="Anthropic" />
+                    <title value="Claude 3.5 Sonnet" />
+                    <usage>
+                      <list>
+                        <option value="chat" />
+                        <option value="edit" />
+                      </list>
+                    </usage>
+                  </llm>
+                </llm>
+              </chat>
+              <chat>
+                <internalId value="26ac815b-5db9-488b-be0b-ab174fbc5646" />
+                <llm>
+                  <llm>
+                    <model value="anthropic/claude-3-5-sonnet-20240620" />
+                    <provider value="Anthropic" />
+                    <title value="Claude 3.5 Sonnet" />
+                    <usage>
+                      <list>
+                        <option value="chat" />
+                        <option value="edit" />
+                      </list>
+                    </usage>
+                  </llm>
+                </llm>
+              </chat>
+              <chat>
+                <internalId value="8ab39b26-cdda-4256-878f-e0416e66bbea" />
+                <llm>
+                  <llm>
+                    <model value="anthropic/claude-3-5-sonnet-20240620" />
+                    <provider value="Anthropic" />
+                    <title value="Claude 3.5 Sonnet" />
+                    <usage>
+                      <list>
+                        <option value="chat" />
+                        <option value="edit" />
+                      </list>
+                    </usage>
+                  </llm>
+                </llm>
+              </chat>
+              <chat>
+                <internalId value="f79a288a-adc5-4d45-a069-4bf024d90236" />
+                <llm>
+                  <llm>
+                    <model value="anthropic/claude-3-5-sonnet-20240620" />
+                    <provider value="Anthropic" />
+                    <title value="Claude 3.5 Sonnet" />
+                    <usage>
+                      <list>
+                        <option value="chat" />
+                        <option value="edit" />
+                      </list>
+                    </usage>
+                  </llm>
+                </llm>
+              </chat>
+              <chat>
+                <internalId value="20bc02fd-c6b5-4590-a00b-b7012a630ef4" />
+                <llm>
+                  <llm>
+                    <model value="anthropic/claude-3-5-sonnet-20240620" />
+                    <provider value="Anthropic" />
+                    <title value="Claude 3.5 Sonnet" />
+                    <usage>
+                      <list>
+                        <option value="chat" />
+                        <option value="edit" />
+                      </list>
+                    </usage>
+                  </llm>
+                </llm>
+              </chat>
+            </list>
+          </chats>
+          <defaultLlm>
+            <llm>
+              <model value="anthropic/claude-3-5-sonnet-20240620" />
+              <provider value="Anthropic" />
+              <tags>
+                <list>
+                  <option value="gateway" />
+                  <option value="accuracy" />
+                  <option value="recommended" />
+                  <option value="free" />
+                </list>
+              </tags>
+              <title value="Claude 3.5 Sonnet" />
+              <usage>
+                <list>
+                  <option value="chat" />
+                  <option value="edit" />
+                </list>
+              </usage>
+            </llm>
+          </defaultLlm>
+        </AccountData>
+      </list>
+    </accountData>
+  </component>
+</project>

.idea/misc.xml

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
-  <component name="ProjectRootManager" version="2" languageLevel="JDK_21" default="true" project-jdk-name="17" project-jdk-type="JavaSDK">
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_21" default="true" project-jdk-name="21" project-jdk-type="JavaSDK">
     <output url="file://$PROJECT_DIR$/out" />
   </component>
 </project>

.idea/runConfigurations/AppLoader.xml

@@ -0,0 +1,17 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="AppLoader" type="Application" factoryName="Application" nameIsGenerated="true">
+    <option name="ALTERNATIVE_JRE_PATH" value="21" />
+    <option name="MAIN_CLASS_NAME" value="net.torvald.tsvm.AppLoader" />
+    <module name="tsvm_executable" />
+    <option name="VM_PARAMETERS" value="-ea --upgrade-module-path=lib/compiler-23.1.10.jar:lib/compiler-management-23.1.10.jar:lib/truffle-compiler-23.1.10.jar:lib/truffle-api-23.1.10.jar:lib/truffle-runtime-23.1.10.jar:lib/polyglot-23.1.10.jar:lib/collections-23.1.10.jar:lib/word-23.1.10.jar:lib/nativeimage-23.1.10.jar:lib/jniutils-23.1.10.jar -XX:+UnlockExperimentalVMOptions -XX:+EnableJVMCI -XX:+UseZGC -XX:+UseDynamicNumberOfGCThreads --add-exports=java.base/jdk.internal.misc=jdk.internal.vm.compiler" />
+    <extension name="coverage">
+      <pattern>
+        <option name="PATTERN" value="net.torvald.tsvm.*" />
+        <option name="ENABLED" value="true" />
+      </pattern>
+    </extension>
+    <method v="2">
+      <option name="Make" enabled="true" />
+    </method>
+  </configuration>
+</component>

.idea/runConfigurations/TerranBASIC.xml

@@ -0,0 +1,16 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="TerranBASIC" type="Application" factoryName="Application" nameIsGenerated="true">
+    <option name="MAIN_CLASS_NAME" value="net.torvald.tsvm.TerranBASIC" />
+    <module name="TerranBASICexecutable" />
+    <option name="VM_PARAMETERS" value="--upgrade-module-path=lib/compiler-23.1.10.jar:lib/compiler-management-23.1.10.jar:lib/truffle-compiler-23.1.10.jar:lib/truffle-api-23.1.10.jar:lib/truffle-runtime-23.1.10.jar:lib/polyglot-23.1.10.jar:lib/collections-23.1.10.jar:lib/word-23.1.10.jar:lib/nativeimage-23.1.10.jar:lib/jniutils-23.1.10.jar -XX:+UnlockExperimentalVMOptions -XX:+EnableJVMCI --add-exports=java.base/jdk.internal.misc=jdk.internal.vm.compiler" />
+    <extension name="coverage">
+      <pattern>
+        <option name="PATTERN" value="net.torvald.tsvm.*" />
+        <option name="ENABLED" value="true" />
+      </pattern>
+    </extension>
+    <method v="2">
+      <option name="Make" enabled="true" />
+    </method>
+  </configuration>
+</component>

.idea/runConfigurations/TsvmEmulator.xml

@@ -0,0 +1,16 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="TsvmEmulator" type="Application" factoryName="Application" nameIsGenerated="true">
+    <option name="MAIN_CLASS_NAME" value="net.torvald.tsvm.TsvmEmulator" />
+    <module name="tsvm_executable" />
+    <option name="VM_PARAMETERS" value="-ea --upgrade-module-path=lib/compiler-23.1.10.jar:lib/compiler-management-23.1.10.jar:lib/truffle-compiler-23.1.10.jar:lib/truffle-api-23.1.10.jar:lib/truffle-runtime-23.1.10.jar:lib/polyglot-23.1.10.jar:lib/collections-23.1.10.jar:lib/word-23.1.10.jar:lib/nativeimage-23.1.10.jar:lib/jniutils-23.1.10.jar -XX:+UnlockExperimentalVMOptions -XX:+EnableJVMCI -XX:+UseZGC -XX:+UseDynamicNumberOfGCThreads --add-exports=java.base/jdk.internal.misc=jdk.internal.vm.compiler" />
+    <extension name="coverage">
+      <pattern>
+        <option name="PATTERN" value="net.torvald.tsvm.*" />
+        <option name="ENABLED" value="true" />
+      </pattern>
+    </extension>
+    <method v="2">
+      <option name="Make" enabled="true" />
+    </method>
+  </configuration>
+</component>

.idea/vcs.xml

@@ -2,5 +2,7 @@
 <project version="4">
   <component name="VcsDirectoryMappings">
     <mapping directory="$PROJECT_DIR$" vcs="Git" />
+    <mapping directory="$PROJECT_DIR$/assets/disk0/home/tetrino" vcs="Git" />
+    <mapping directory="$PROJECT_DIR$/assets/disk0/home/tvnes" vcs="Git" />
   </component>
 </project>

2taud.sh

@@ -0,0 +1,6 @@
+#!/usr/bin/env fish
+
+for f in *.mod; python3 mod2taud.py $f assets/disk0/(basename $f .mod).taud; end
+for f in *.s3m; python3 s3m2taud.py $f assets/disk0/(basename $f .s3m).taud; end
+for f in *.it; python3 it2taud.py $f assets/disk0/(basename $f .it).taud; end
+for f in *.xm; python3 xm2taud.py $f assets/disk0/(basename $f .xm).taud; end

CLAUDE.md

@@ -12,6 +12,32 @@ This file provides guidance to Claude Code (claude.ai/code) when working with co
 - TerranBASIC integration
 - Multiple platform build system
 
+## Documentations
+
+Documentation for TSVM and TVDOS are available on `./doc/*.tex` as machine-readable format.
+
+Documentatino for TSVM architecture is available on `terranmon.txt`
+
+## Reference Materials
+
+Third-party source-code references that inform TSVM implementations live in
+`reference_materials/<topic>/`. Each topic folder has a `README.md` that
+summarises the takeaway and points back into the verbatim source files.
+**Consult these before reimplementing tracker / codec / DSP behaviour from
+memory** — TSVM aims to match the audible behaviour of the originals.
+
+Current topics:
+
+- `reference_materials/tracker_filter/` — Impulse Tracker / OpenMPT / Schism
+  Tracker resonant low-pass filter source. Defines the cutoff formula, the
+  resonance damping curve, and the **IIR-only 2-pole topology** (NOT a
+  biquad — no feedforward x[n−1] / x[n−2] terms) that `AudioAdapter.kt` uses
+  for Taud playback.
+
+When fetching new references, copy the relevant upstream files verbatim into
+a topic folder, write a `README.md` summarising the relevant maths /
+algorithms with file:line citations, and add an entry here.
+
 ## Architecture
 
 ### Core Components

TAUD_NOTE_EFFECTS.md

@@ -0,0 +1,965 @@
+# Taud Tracker Effect Command Reference
+
+Taud is a tracker-style music format derived from ScreamTracker 3's pattern command set, extended to 16-bit effect arguments and a 4096-tone equal-temperament pitch grid. This document defines every effect command a Taud engine must implement. Each command entry has three parts: a plain explanation for composers, compatibility notes for converting patterns from ScreamTracker 3 (ST3), ImpulseTracker (IT) or ProTracker (PT), and implementation details for engine writers.
+
+---
+
+## 1. Sound device
+
+- **Bit depth:** 8-bit unsigned throughout, including the final mixdown.
+- **Sample rate:** fixed at 32000 Hz.
+- **Output channels:** strictly stereo; the mix bus always produces a two-channel frame even for mono-source samples.
+
+Internal accumulators may widen to 16 or 32 bits during mixing and effect computation, but stored samples and final output are 8-bit.
+
+## 2. Pitch system — 4096-TET
+
+One octave spans **4096 pitch units** ($1000 exactly). A 12-TET semitone therefore equals **4096 ÷ 12 ≈ 341.333 units** (≈ $0155.55), which is not an integer; this irrationality is a deliberate consequence of choosing a microtonal native grid. Implementations store channel pitch as a signed integer in Taud units, and convert to playback rate using
+
+```
+playback_rate = reference_rate × 2 ^ (pitch_units / 4096)
+```
+
+Commonly used intervals in Taud units are listed below; all are rounded to the nearest integer.
+
+| Interval | Units (exact) | Hex (rounded) |
+|---|---|---|
+| Octave | 4096 | $1000 |
+| Perfect fifth (7 ST) | 2389.33 | $0955 |
+| Tritone (6 ST) | 2048 | $0800 |
+| Major third (4 ST) | 1365.33 | $0555 |
+| Minor third (3 ST) | 1024 | $0400 |
+| 1 semitone | 341.33 | $0155 |
+| 1/8 semitone (1 finetune) | 42.67 | $002B |
+| 1/16 semitone | 21.33 | $0015 |
+| 1/64 semitone | 5.33 | $0005 |
+| 1 cent (1/100 semitone) | 3.41 | $0003 |
+
+## 3. Volume system
+
+Per-note and per-channel volume runs from **$00 (silent) to $3F (full)**, a 6-bit range narrower than ST3's 0..$40. Global volume (effect V) runs 0..$FF; this wider range lets the mix bus scale the summed channel output without disturbing individual note volumes. The per-frame mix chain per channel is
+
+```
+mix = sample × note_vol × channel_vol × global_vol >> normalisation_shift
+```
+
+with saturation applied before the 8-bit stereo output.
+
+## 4. Rows, ticks, patterns, cues
+
+A pattern is a rectangular grid of rows and channels; each cell holds one note event. Playback divides each row into `speed` ticks (effect A); tempo (effect T) sets the duration of one tick. At 125 BPM and speed 6, one row takes 120 ms and one tick 20 ms. Songs play patterns in a cue sequence; effects B and C navigate this sequence.
+
+## 5. Default parameters at song start
+
+| Parameter | Value |
+|---|---|
+| Speed | $06 (6 ticks/row) |
+| Tempo byte | $65 (125 BPM; see effect T for the $18 offset) |
+| Global volume | $80 (mid-scale) |
+| Channel volume | $3F (full) |
+| Pan (all channels) | $80 (centre) |
+| cue index | $0000 |
+
+## 6. Effect memory groups
+
+Most effects recall their last non-zero argument when re-issued with $0000. Unlike ST3, which shares one memory slot across most effects, Taud groups memories into four cohorts plus private slots:
+
+- **E and F share one slot** (pitch slide down and up). Issuing E $0000 recalls the last E-or-F argument and re-applies it as a down-slide; F $0000 does the same as an up-slide.
+- **G has its own slot** (tone portamento).
+- **H and U share one slot** (vibrato speed and depth are jointly recalled; the last-written values persist across both commands).
+- **R has its own slot** (tremolo).
+
+Every other memory-carrying effect (D, I, J, K, L, O, Q, and others) has a private slot.
+
+## 7. Opcode and argument format
+
+Opcodes are single base-36 digits (0-9, then A-Z); arguments are 16-bit hexadecimal values prefixed with `$`. A cell is notated `OPCODE $HHLL` where HH is the high byte and LL is the low byte. Where an effect partitions its argument into sub-fields (for instance, H's speed and depth), the split is spelled out in the command description.
+
+---
+
+# The effects
+
+## A $xx00 — Set tick speed to $xx
+
+**Plain.** Sets how many ticks each row contains. Lower values make rows shorter and per-tick effects (slides, vibrato) develop faster; higher values stretch the row and give effects more iterations.
+
+**Compatibility.** ST3 `Axx` maps one-to-one: Taud `A $xx00`. ST3 `A00` is a no-op; Taud `A $0000` is likewise ignored. ProTracker `Fxx` with `xx < $20` maps to Taud `A $xx00`; `Fxx` with `xx ≥ $20` maps to T instead (see T).
+
+**Implementation.** If the high byte is non-zero, write it to `ticks_per_row`; the low byte is reserved and must be zero. The change takes effect from the row on which the A command appears. There is no memory for A.
+
+---
+
+## B $xxyy — Jump to cue $xxyy
+
+**Plain.** Finishes the current row, then continues playback at row 0 of the pattern at cue position $xxyy. Use this to create song-level jumps, loops, or branching structures.
+
+**Compatibility.** ST3 `Bxx` jumps to an 8-bit cue and maps to Taud `B $00xx`. The extended 16-bit range means Taud songs may have up to $10000 cue entries.
+
+**Implementation.** On the last tick of the current row, set the next cue index to the argument and the next row to 0. If the argument exceeds the song length, wrap to the song's defined restart position (cue $0000 by default). Jumps are detected by a visited `(cue, row)` set so that pathological loops do not prevent song-length computation, though they do not interrupt actual playback. There is no memory for B.
+
+**Simultaneous B and C on the same row.** If a B command appears in the same row as a C command (on any channel), both fire: B chooses the cue, C chooses the row within that cue. If the two commands appear on different channels, channel priority is **ascending channel index** — the lowest-numbered channel carrying either effect wins its parameter. If both appear on the same channel row (only possible if one is a volume-column equivalent), the effect column takes precedence.
+
+---
+
+## C $xxyy — Break pattern to row $xxyy
+
+**Plain.** Finishes the current row, then skips ahead to row $xxyy of the **next** pattern in the cue sequence.
+
+**Compatibility.** ST3 stores `Cxx` as **BCD** (so on-disk `$10` means decimal row 10); Taud stores the argument as plain binary. When converting from ST3, decode with `row = (byte >> 4) × 10 + (byte & $0F)`. Valid ST3 source bytes are those representing decimal 0..63; out-of-range BCD bytes should clamp to row 0 on import. When exporting back to ST3, encode with `byte = ((row / 10) << 4) | (row % 10)`, clamped at row 63.
+
+**Implementation.** On the last tick of the current row, advance the cue index by 1 (or honour a co-occurring B), then set the next row to the argument. If the argument exceeds the destination pattern's row count, start the destination pattern at row 0. There is no memory for C.
+
+---
+
+## D $xy00 — Volume slide (multiple forms)
+
+D's 16-bit argument encodes four mutually exclusive modes using the top nibble and the following byte. All forms operate on the channel's current volume and clip to $00..$3F after each step.
+
+### D $0y00 — Volume slide down by $y per non-first tick
+
+**Plain.** Each tick after tick 0, volume decreases by $y. A D $0400 at speed 8 reduces volume by $1C over the row.
+
+**Compatibility.** ST3 `Dx0` (volume slide down) maps to Taud `D $0x00`. The ST3 volume cap was $40; Taud's is $3F — a very high-volume sample reaching $40 in ST3 will snap to $3F in Taud.
+
+**Implementation.** On ticks > 0, subtract the low nibble of the high byte from `channel_volume`; clamp at $00. Memory is private to D and is keyed on the full original byte (so D $0000 recalls whatever form last ran).
+
+### D $x000 — Volume slide up by $x per non-first tick
+
+**Plain.** Each tick after tick 0, volume increases by $x. Capped at $3F.
+
+**Compatibility.** ST3 `D0y` (volume slide up) maps to Taud `D $y000`.
+
+**Implementation.** On ticks > 0, add the high nibble of the high byte to `channel_volume`; clamp at $3F.
+
+### D $Fy00 — Fine volume slide down by $y on tick 0
+
+**Plain.** Applies a one-shot volume reduction of $y on tick 0 only. Independent of speed. A D $FF00 behaves as a fine slide up by $F (so a request for "down by F" is reinterpreted; see below).
+
+**Compatibility.** ST3 `DFy` maps directly. The $FF edge case is preserved: ST3 treats `DFF` as fine slide up by $F rather than fine slide down by $F, and Taud follows suit.
+
+**Implementation.** On tick 0 only, subtract the low nibble of the high byte from `channel_volume`. If the low nibble is $0, treat as fine-slide-up by $F. If the high byte is $FF, treat as fine-slide-up by $F.
+
+### D $xF00 — Fine volume slide up by $x on tick 0
+
+**Plain.** One-shot volume increase of $x on tick 0 only.
+
+**Compatibility.** ST3 `DxF` maps directly. Volume cap is $3F, lower than ST3's $40.
+
+**Implementation.** On tick 0 only, add the high nibble to `channel_volume`; clamp at $3F.
+
+---
+
+## E $xxxx — Pitch slide down by $xxxx
+
+**Plain.** Lowers the channel's pitch by the argument per tick. The coarse argument has **two distinct interpretations** chosen by the song-table `f` flag (effect `1`, bit 1):
+
+- **Linear mode** (`f` unset, default): the argument is a value in the 4096-TET pitch grid, subtracted directly from the stored pitch. `E $0155` ≈ one semitone per tick.
+- **Amiga (cycle-based) mode** (`f` set): the argument is a **raw ProTracker/ST3 period unit count** — the same byte the original tracker stored on disk, *unscaled*. The engine converts the channel's stored 4096-TET pitch back to an Amiga period, subtracts the argument from that period directly, then converts the result back to 4096-TET. `E $0001` therefore corresponds to PT `201` and produces the characteristic non-linear pitch drift of ProTracker-style slides (lower pitches drift more slowly in semitone terms than higher pitches).
+
+Because Amiga period units fit in a single byte (PT/ST3 max value $FF), the coarse range in Amiga mode never approaches the $F000 fine-slide marker, so the same argument-format selector still distinguishes coarse from fine. **Fine slides (`E $Fxxx`) follow the same dual-interpretation rule as coarse**: in linear mode the low 12 bits are 4096-TET units; in Amiga mode they are raw tracker period units (the PT `E2x` / ST3 `EFx` or `EEx` digit), applied once per row at tick 0 in period space. A coarse slide uses the full value range; a fine slide applies only once per row.
+
+Coarse and fine modes are distinguished by the high nibble of the argument:
+
+- `E $0001..$EFFF` — coarse slide: subtracts the full argument from pitch each tick after tick 0. A slide of $0155 drops pitch by one semitone per tick.
+- `E $F000..$FFFF` — fine slide: on tick 0 only, subtracts `arg & $0FFF` from pitch.
+- `E $0000` — recalls the last E-or-F argument and applies it as a down-slide, preserving the original form (coarse or fine).
+
+**Compatibility.** ST3 pitch slides operate on Amiga periods or linear slide units; Taud's storage depends on the song-table mode flag:
+
+- **Linear-source ST3 song** (`linear_slides` set in S3M flags → Taud `f` bit clear):
+  - ST3 `Exx` coarse (where `xx < $E0`) → Taud `E round($00xx × 64/3)` (1 ST3 coarse unit = 1/16 semitone = 64/3 ≈ 21.33 Taud units, rounded).
+  - ST3 `EFx` fine → Taud `E $F0 round(x × 16/3)` (1 ST3 fine unit = 1/64 semitone = 16/3 ≈ 5.33 Taud units, applied once per row).
+  - ST3 `EEx` extra-fine → Taud `E $F0 round(x × 16/3)` (same unit as fine, applied once per row).
+
+- **Amiga-source ST3/PT song** (`linear_slides` clear → Taud `f` bit set):
+  - ST3 `Exx` coarse / PT `2xx` → Taud `E $00xx` **verbatim**, with no `× 64/3` scaling. The engine reads the stored byte as Amiga period units and applies it in period space, recovering the original tracker's exact period-step count.
+  - ST3 `EFx` fine / `EEx` extra-fine / PT `E2x` → Taud `E $F00x` **verbatim** (raw period-unit nibble in the low 4 bits), with no `× 16/3` scaling. The engine performs the once-per-row fine slide in Amiga period space, mirroring the coarse arithmetic.
+
+The Amiga-mode flag therefore controls **two** decoder behaviours simultaneously: (a) which numeric scale the converter should have used when emitting coarse arguments, and (b) which arithmetic the engine performs on those arguments per tick. Converters MUST set bit 1 (`f`) of the song-table flags byte whenever they emit raw period-unit coarse arguments, and MUST NOT mix the two scales within one Taud song.
+
+Because E and F share memory in Taud (narrower than ST3's broad shared memory), an ST3 song that used `E00` or `F00` to recall a D, G, or Q argument will break on import; the converter must eagerly resolve ST3 recalls into explicit Taud arguments rather than relying on memory.
+
+**Implementation.** Per-tick processing:
+
+```
+on row start:
+    raw = arg
+    if raw == 0: raw = memory_EF
+    else: memory_EF = raw
+    if (raw & $F000) == $F000:          # fine, applied once on tick 0
+        mag = raw & $0FFF
+        if amiga_mode:
+            # mag is a raw tracker period-unit count; subtract pitch ⇒ add period.
+            pitch = amiga_slide_down(pitch, mag)
+        else:
+            pitch -= mag
+        mode_this_row = FINE
+    else:                                # coarse
+        slide_amount_this_row = raw
+        mode_this_row = COARSE
+
+on tick > 0:
+    if mode_this_row == COARSE:
+        if amiga_mode:
+            # slide_amount_this_row is a raw tracker period-unit count (no × 64/3 scaling).
+            # period = AMIGA_BASE_PERIOD × 2^(−(pitch − C4) / 4096)
+            # period_new = period + slide_amount_this_row     # E subtracts pitch ⇒ adds period
+            # pitch = C4 + 4096 × log2(AMIGA_BASE_PERIOD / period_new)
+            pitch = amiga_slide_down(pitch, slide_amount_this_row)
+        else:
+            pitch -= slide_amount_this_row
+```
+
+Glissando control (S $1x) snaps the output pitch to the nearest semitone after every slide application; see S $1x.
+
+---
+
+## F $xxxx — Pitch slide up by $xxxx
+
+**Plain.** Raises the channel's pitch by the argument per tick, with the same mode-selection scheme as E. Coarse, fine, memory behaviour, and Amiga-mode handling are identical in form but inverted in direction. The same dual-interpretation rule applies to **both** coarse and fine arguments: 4096-TET units in linear mode, raw tracker period units in Amiga mode.
+
+**Compatibility.** Same as E. In linear-source songs, ST3 `Fxx` coarse converts using `round(x × 64/3)` and `FFx`/`FEx` fine/extra-fine use `round(x × 16/3)`. In Amiga-source songs (PT or S3M with `linear_slides` clear), both forms are stored verbatim: `Fxx` coarse → `F $00xx`, and `FFx`/`FEx` fine/extra-fine / PT `E1x` → `F $F00x`. F and E share one memory slot in Taud. Amiga-mode behaviour is controlled by the same `f` flag as E; under that flag, both coarse (per-tick) and fine (tick-0 only) F slides are applied in period space.
+
+**Implementation.** As for E, but add instead of subtract. No upper pitch cap is defined by the effect itself, but the sample-rate conversion at the mixer will saturate well before arithmetic overflow at reasonable playing ranges.
+
+---
+
+## G $xxxx — Tone portamento with speed $xxxx
+
+**Plain.** Slides the channel's current pitch toward the note specified in the same row, at $xxxx Taud units per tick (after tick 0), stopping when the target is reached. A row with G and a note does **not** re-trigger the sample — the note's pitch becomes the portamento target and the already-sounding sample continues at its current pitch.
+
+**Compatibility.** ST3 `Gxx` uses an 8-bit value in period-table units; convert to Taud using the same `round(× 64/3)` scale as E/F coarse (1/16 semitone per ST3 slide unit). ST3 linear mode is the expected import source; Amiga-mode G sources should be treated as linear. G has its **own** memory slot in both ST3 and Taud, so conversion is straightforward and does not suffer the shared-memory problem of E/F.
+
+**Implementation.**
+
+```
+on row parse:
+    if row has note and G effect:
+        target_pitch = period_for(note)
+        # do NOT re-trigger sample
+    if arg != 0:
+        memory_G = arg
+    speed_this_row = memory_G
+
+on tick > 0:
+    if target_pitch set:
+        delta = sign(target_pitch - pitch) × speed_this_row
+        pitch += delta
+        if sign crossed target: pitch = target_pitch; target_pitch = None
+```
+
+Glissando (S $1x) snaps the output frequency to the nearest semitone ($0155 step approximation) after each advance without changing the internal pitch counter; it affects only what the mixer sees.
+
+---
+
+## H $xxyy — Vibrato with speed $xx and depth $yy
+
+**Plain.** Modulates pitch with a low-frequency oscillator (LFO). `$xx` is the LFO speed (high byte), `$yy` is the depth (low byte). On H rows the LFO accumulator advances at `$xx × 4` per tick through a 256-entry lookup of the selected waveform (see S $3x). The current pitch offset is added to the channel's base pitch for the duration of each tick.
+
+**Compatibility.** ST3 `Hxy` uses 4-bit nibbles for speed and depth; convert by nibble-repeating each into Taud's bytes: ST3 `H27` → Taud `H $2277`. This preserves the effective LFO rate and peak depth. H and U share memory in Taud (they did in ST3 too).
+
+Unlike ProTracker, ST3 vibrato fires on tick 0 as well; Taud follows ST3.
+
+**Implementation.** The reference sine table is OpenMPT's 64-entry 8-bit table, indexed `pos >> 2` through a 256-entry logical LFO (equivalently, a 256-sample 4×-oversampled sine peaking at ±$7F):
+
+```
+ModSinusTable[64] =
+    00 0C 19 25 31 3C 47 51 5A 62 6A 70 75 7A 7D 7E
+    7F 7E 7D 7A 75 70 6A 62 5A 51 47 3C 31 25 19 0C
+    00 F4 E7 DB CF C4 B9 AF A6 9E 96 90 8B 86 83 82
+    81 82 83 86 8B 90 96 9E A6 AF B9 C4 CF DB E7 F4
+```
+
+Per row/tick:
+
+```
+on row parse (H):
+    if (arg >> 8)  != 0: memory_HU.speed = arg >> 8
+    if (arg & $FF) != 0: memory_HU.depth = arg & $FF
+
+on every tick (including tick 0):
+    sine = ModSinusTable[(lfo_pos >> 2) & $3F]    # signed -$80..+$7F
+    pitch_delta = (sine × memory_HU.depth) >> 6
+    applied_pitch = base_pitch + pitch_delta
+    lfo_pos = (lfo_pos + memory_HU.speed × 4) & $FF
+```
+
+At maximum speed and depth ($FFFF), peak `pitch_delta` is `$7F × $FF >> 6 ≈ $1FA` — about 1.5 semitones. On a fresh note, if the current LFO waveform retrigger bit is clear (S $3x with $x < $4), `lfo_pos` resets to 0. When the waveform is "random", a fresh random value is drawn every tick rather than read from the table.
+
+---
+
+## U $xxyy — Fine vibrato with speed $xx and depth $yy
+
+**Plain.** Same LFO as H but four times finer in pitch — useful for subtle microtonal warbles.
+
+**Compatibility.** ST3 `Uxy` uses nibbles; nibble-repeat each to convert. U shares memory with H.
+
+**Implementation.** Identical to H except the shift is 8 instead of 6:
+
+```
+pitch_delta = (sine × memory_HU.depth) >> 8
+```
+
+Peak at maximum settings: $7F × $FF >> 8 ≈ $7E, about 0.4 semitone — exactly a quarter of H's peak.
+
+---
+
+## I $xxyy — Tremor with on-time $xx and off-time $yy
+
+**Plain.** Rapidly gates the channel on and off. Volume plays normally for `$xx + 1` ticks, then mutes for `$yy + 1` ticks, repeating. Counters persist across rows and only reset on a fresh I row with a new argument.
+
+**Compatibility.** ST3 `Ixy` uses nibbles (`$xy`) with the same semantics; convert by nibble-repeating each into Taud bytes: ST3 `I47` → Taud `I $4477`. The `+1` behaviour on both counters comes from ProTracker and is preserved throughout. Memory is private.
+
+**Implementation.**
+
+```
+on row parse (I):
+    if arg != 0: memory_I = arg
+    on_time  = ((memory_I >> 8)  & $FF) + 1
+    off_time = ( memory_I        & $FF) + 1
+
+on every tick:
+    if phase == ON:
+        play at full channel volume
+        tick_in_phase += 1
+        if tick_in_phase >= on_time: phase = OFF; tick_in_phase = 0
+    else:
+        force output volume to 0 (base volume preserved for later effects)
+        tick_in_phase += 1
+        if tick_in_phase >= off_time: phase = ON; tick_in_phase = 0
+```
+
+A zero `$xx` or `$yy` input becomes 1 tick after the `+1`, never zero.
+
+---
+
+## J $xxyy — Microtonal arpeggio with offsets $xx00 and $yy00
+
+**Plain.** Cycles the playing pitch through three values across consecutive ticks: the note, the note plus `$xx00` Taud units, and the note plus `$yy00` Taud units, repeating. At the default 50 Hz tick rate (speed 6, 125 BPM), this produces a classic chord-arpeggio effect; because Taud's grid is 4096-TET, the intervals can be microtonal.
+
+The encoding places each 8-bit offset byte into the **high byte** of a 16-bit pitch delta, giving 256 discrete intervals per arp voice with a resolution of $0100 ≈ 0.75 semitone per step. This is coarser than E/F's 16-bit slides, but adequate for arpeggios and well-suited to non-12-TET intervals.
+
+**Compatibility.** ST3 `Jxy` uses nibbles as 12-TET semitones; Taud uses bytes as $0100-scaled 4096-TET offsets. The conversion is therefore lossy — 12-TET intervals that are not multiples of 3 semitones incur ±25 cent rounding error. The table below gives the best Taud byte for each 12-TET semitone offset:
+
+| Semitones | Taud byte | Taud units | Error (cents) |
+|---|---|---|---|
+| 0 | $00 | 0 | 0 |
+| 1 | $01 | 256 | −25 |
+| 2 | $03 | 768 | +25 |
+| 3 | $04 | 1024 | 0 |
+| 4 | $05 | 1280 | −25 |
+| 5 | $07 | 1792 | +25 |
+| 6 | $08 | 2048 | 0 |
+| 7 | $09 | 2304 | −25 |
+| 8 | $0B | 2816 | +25 |
+| 9 | $0C | 3072 | 0 |
+| 10 | $0D | 3328 | −25 |
+| 11 | $0F | 3840 | +25 |
+| 12 | $10 | 4096 | 0 |
+
+For example, ST3 `J37` (minor chord) imports as Taud `J $0409`; ST3 `J47` (major chord) as Taud `J $0509`. Memory is private and stores the full 16-bit argument.
+
+**Implementation.**
+
+```
+on row parse (J):
+    if arg != 0: memory_J = arg
+    off1 = (memory_J >> 8) & $FF    # high byte
+    off2 =  memory_J       & $FF    # low byte
+
+on every tick:
+    selector = tick_within_row mod 3
+    if selector == 0:   voice_pitch = base_pitch
+    elif selector == 1: voice_pitch = base_pitch + (off1 << 8)
+    elif selector == 2: voice_pitch = base_pitch + (off2 << 8)
+```
+
+The `tick_within_row mod 3` counter resets every row start (so every row begins at `base_pitch`). A subsequent E/F slide after a J row resumes from the last arpeggiated voice's pitch, not from `base_pitch` — this mirrors ST3's `kST3PortaAfterArpeggio` quirk and is deliberately preserved.
+
+---
+
+## K $xy00 — Dual: vibrato continuation and volume slide $xy
+
+**Plain.** **Unimplemented**. On ST3, continues a previously started vibrato (H or U) without retriggering it, while applying a volume slide of `$xy` per non-first tick. Fine volume slides are not available in this form.
+
+**Compatibility.** ST3 `Kxy` maps directly. Implementations must convert K to an explicit pair of commands: `H $0000` (continue with stored speed/depth) combined with volume-column command `1.$xy` (volume slide), and emit both.
+
+**Implementation.** Execute the per-tick vibrato update as if an H command were active with argument $0000 (recall), then execute a D $0y00 or $x000 slide using the bytes of the K argument: high nibble as up-slide, low nibble as down-slide. If both nibbles are non-zero, down-slide takes precedence (matching ST3). K has no memory of its own; it uses H/U's stored speed and depth.
+
+---
+
+## L $xy00 — Dual: tone portamento continuation and volume slide $xy
+
+**Plain.** **Unimplemented**. On ST3, continues a previously started tone portamento (G) without retriggering, while applying a volume slide of `$xy` per non-first tick. Fine volume slides are not available here.
+
+**Compatibility.** ST3 `Lxy` maps directly. Like K, L must be equivalently implemented as `G $0000` plus a volume-column slide.
+
+**Implementation.** Execute the per-tick G update (recalling G's stored speed), then the D slide as in K. L has no memory of its own.
+
+---
+
+## O $xxyy — Set sample offset to $xxyy
+
+**Plain.** On the row where it appears, jumps the sample playhead to byte $xxyy of the sample data. If the sample is looped and the requested offset exceeds the loop end, the offset wraps around through the loop as if playback had reached that point naturally.
+
+**Compatibility.** ST3 `Oxx` is 8-bit, addressing offset `xx × $100`. On import, copy the ST3 byte into Taud's high byte and zero the low byte: Taud `O $xx00`. ProTracker `9xx` maps identically. The Taud 16-bit form allows byte-precise seeking within samples larger than $100 bytes. Memory is private.
+
+**Implementation.** On the row start, set the sample playhead to `arg` (in bytes, relative to the sample's start). Apply the loop-wrap calculation if the sample has loop points and `arg > loop_end`: `arg = loop_start + ((arg - loop_start) mod loop_length)`. The O command does not retrigger the sample; it only relocates the playhead for an already-triggered note.
+
+---
+
+## Q $xy00 — Retrigger note every $y ticks with volume modifier $x
+
+**Plain.** Retriggers the currently playing sample at an interval of `$y` ticks, optionally modifying its volume on each retrigger according to `$x`. The retrigger interval runs across rows until a new Q with a different `$y` or no Q at all.
+
+**Compatibility.** ST3 `Qxy` maps directly. The **`$y == 0` behaviour is preserved from ST3**: the entire effect is ignored (no retrigger, and memory is not updated). Memory is private.
+
+ProTracker `E9x` is equivalent to Taud `Q $0x00` (retrigger only, no volume change).
+
+**Implementation.** A per-channel tick counter advances every tick, including tick 0. When it reaches `$y`, the sample retriggers (keeping current pitch), the counter resets to 0, and the volume modifier `$x` applies. The counter resets only when a row has **no** Q command; successive Q rows share and advance the counter.
+
+The volume modifier table, **computed with arithmetic (no LUT)**, is:
+
+| $x | Action | $x | Action |
+|---|---|---|---|
+| 0 | no change | 8 | no change |
+| 1 | vol − $01 | 9 | vol + $01 |
+| 2 | vol − $02 | A | vol + $02 |
+| 3 | vol − $04 | B | vol + $04 |
+| 4 | vol − $08 | C | vol + $08 |
+| 5 | vol − $10 | D | vol + $10 |
+| 6 | vol × 2 / 3 | E | vol × 3 / 2 |
+| 7 | vol × 1 / 2 | F | vol × 2 |
+
+Multiplicative cases use integer arithmetic: `vol × 2 / 3` is `(vol × 2) / 3` (truncated); `vol × 3 / 2` is `(vol × 3) / 2`; `vol × 1 / 2` is `vol >> 1`; `vol × 2` is `vol << 1`. All results clip to $00..$3F after.
+
+A note previously silenced by a cut (`^^^` or `SCx` earlier in the row) is not retriggered, matching ST3's `kST3RetrigAfterNoteCut` rule.
+
+---
+
+## R $xxyy — Tremolo with speed $xx and depth $yy
+
+**Plain.** Modulates volume with an LFO, symmetrically with H's pitch modulation. `$xx` is LFO speed, `$yy` depth; the waveform is selected by S $4x.
+
+**Compatibility.** ST3 `Rxy` uses nibbles; convert by nibble-repeat. ST3's volume cap is $40; Taud's is $3F — very deep tremolo that would have briefly clipped at $40 in ST3 may clip slightly earlier in Taud. R has its own memory slot (not shared with H/U).
+
+**Implementation.** Identical machinery to H with a larger shift to fit the narrower volume range:
+
+```
+on row parse (R):
+    if (arg >> 8)  != 0: memory_R.speed = arg >> 8
+    if (arg & $FF) != 0: memory_R.depth = arg & $FF
+
+on every tick (including tick 0):
+    sine = ModSinusTable[(lfo_pos >> 2) & $3F]
+    vol_delta = (sine × memory_R.depth) >> 9
+    applied_vol = clamp(base_vol + vol_delta, 0, $3F)
+    lfo_pos = (lfo_pos + memory_R.speed × 4) & $FF
+```
+
+Peak at maximum settings: $7F × $FF >> 9 = $3F — the full volume range. Retrigger behaviour tracks the S $4x waveform nibble bit 2: cleared means retrigger on new note, set means preserve LFO position.
+
+---
+
+## T $xxyy — Tempo set or tempo slide
+
+Taud splits T by which byte carries the value:
+
+### T $xx00 (high byte non-zero) — Set tempo
+
+**Plain.** Sets the Taud tempo byte to `$xx`. The resulting BPM is `$xx + $18`: Taud byte $00 → 24 BPM, $65 → 125 BPM (default), $FF → 279 BPM.
+
+**Compatibility.** ST3 `Txx` (where `xx ∈ $20..$FF`) stores BPM directly; convert with `taud_byte = xx − $18`. Taud byte $08 corresponds to ST3's minimum BPM of 32; Taud bytes below $08 are inexpressible in ST3 and should round up to $08 (BPM 32) when exporting. OpenMPT's extended tempo slides (`T $0x` down, `T $1x` up) in S3M files map to Taud T $00xx — see below.
+
+ProTracker `Fxx` with `xx ≥ $20` maps to Taud `T $(xx − $18)00`; `Fxx` with `xx < $20` maps to A (speed) instead.
+
+**Implementation.** If the high byte is non-zero, set `tempo_byte = arg >> 8`; derive `BPM = tempo_byte + $18`; compute tick duration as `samples_per_tick = 32000 × 5 / (BPM × 2) = 80000 / BPM` (integer truncated) at the fixed 32000 Hz output rate. Example: BPM 125 → 640 samples per tick; BPM 24 → 3333 samples per tick; BPM 279 → 286 samples per tick. There is no memory for set-tempo.
+
+### T $00xy (high byte zero) — Tempo slide
+
+**Plain.** Adjusts the tempo continuously during the row. `$00_0y` (low nibble under a zero high nibble within the low byte) slides BPM down by `$y` per non-first tick; `$00_1y` slides up. Out-of-range encodings ($00_20 through $00_FF) are reserved and behave as no-ops.
+
+**Compatibility.** ST3 itself has only the set form; the slide forms originate in the OpenMPT/Schism extension of S3M. On export to strict ST3, slide forms are unrepresentable and should be approximated as an equivalent set-tempo on a later row.
+
+**Implementation.**
+
+```
+on row parse (T with high byte == 0):
+    low = arg & $FF
+    if (low & $F0) == $00:
+        slide_dir = DOWN
+        slide_amount = low & $0F
+    elif (low & $F0) == $10:
+        slide_dir = UP
+        slide_amount = low & $0F
+    else:
+        ignore row
+
+on tick > 0 (if slide armed):
+    if slide_dir == DOWN: tempo_byte = max($00, tempo_byte - slide_amount)
+    else:                 tempo_byte = min($FF, tempo_byte + slide_amount)
+    recompute samples_per_tick for next tick
+```
+
+A tempo slide's memory slot is separate from the set-tempo path and is private to T-slide.
+
+---
+
+## V $xx00 — Set global volume to $xx
+
+**Plain.** Sets the global mix bus volume (0..$FF). $00 is silence; $FF is full. The default is $80.
+
+**Compatibility.** ST3's global volume is 0..$40; convert with `taud_v = st3_v × 4`, clamped at $FF. On export, `st3_v = taud_v >> 2`, clamped at $40. IT's global volume is 0..$80; convert with `taud_v = it_v × 2`, clamped at $FF. On IT, the very first `V 00` command must be resolved as the song's initial global volume.
+
+**Implementation.** Write the high byte to `global_volume` on the row the command appears. The low byte is reserved. ST3's `kST3NoMutedChannels` rule applies: V on a muted channel is ignored by ST3; for strict-compatible playback Taud follows suit, but new Taud compositions should avoid muting channels that carry global effects.
+
+---
+
+## W $xy00 — Global volume slide
+
+**Plain.** Similar to `D $xy00`, but applies to the global volume.
+
+**Compatibility.** IT `Wxy` maps directly.
+
+**Implementation.** See effect D, apply to the global volume instead.
+
+---
+
+## X $xx00 — Fine Set Panning
+
+**Plain.** **Unimplemented**. On IT, sets the panning position of the current channel, $00 being full-left and $FF being full-right.
+
+**Compatibility.** Convert to `S $80xx`.
+
+**Implementation.** Not applicable.
+
+---
+
+## Y $xxyy — Panbrello (panning vibrato) with speed $xx and depth $yy
+
+**Plain.** Modulates panning with an LFO, symmetrically with H's pitch modulation. `$xx` is LFO speed, `$yy` depth; the waveform is selected by S $5x.
+
+**Compatibility.** IT `Yxy` uses nibbles; convert by nibble-repeat. IT's panning cap is $40; Taud's is $3F — very deep vibrato that would have briefly clipped at $40 in IT may clip slightly earlier in Taud. Y has its own memory slot.
+
+**Implementation.** Identical machinery to H with a larger shift to fit the narrower volume range:
+
+```
+on row parse (Y):
+    if (arg >> 8)  != 0: memory_Y.speed = arg >> 8
+    if (arg & $FF) != 0: memory_Y.depth = arg & $FF
+
+on every tick (including tick 0):
+    sine = ModSinusTable[(lfo_pos >> 2) & $3F]
+    vol_delta = (sine × memory_Y.depth) >> 9
+    applied_vol = clamp(base_vol + vol_delta, 0, $3F)
+    lfo_pos = (lfo_pos + memory_Y.speed × 4) & $FF
+```
+
+Peak at maximum settings: $7F × $FF >> 9 = $3F — the full panning range. Retrigger behaviour tracks the S $5x waveform nibble bit 2: cleared means retrigger on new note, set means preserve LFO position.
+
+---
+
+## 8 $xyzz — Bitcrusher
+
+**Plain.** Applies Bitcrusher to the current voice.
+
+- x: clipping mode. 0: clamp, 1: fold, 2: modulus
+- y: bit depth (1..15). 8..15 has no effect on TSVM audio adapter (already operates on 8 bits)
+- z: sample skip (0..255). 0: no skip, 1: use every 2nd samples, 2: use every 3rd samples, ..., 255: use every 256th samples
+- `8 0000` will disable the bitcrusher
+
+**Compatibility.** Unique to Taud. No compatible equivalent exists.
+
+**Implementation.** TODO
+
+---
+
+# The S subcommand family
+
+S is a multiplexing opcode; the **high nibble of the high byte** selects the sub-effect, and the remainder is the sub-argument.
+
+## S $1x00 — PT/ST3/IT Glissando control
+
+**Plain.** `$1000` turns glissando off; `$1100` turns it on. When on, tone portamento (G) output is quantised to the nearest semitone ($0155 approximation) before being sent to the mixer. The internal G pitch counter still advances smoothly; only the audible pitch steps. **This command is implemented sorely for ST3/IT compatibility** and therefore only works in 12-TET context.
+
+**Compatibility.** ST3/IT `S10`/`S11` and PT `E30`/`E31` maps directly. In Taud, "nearest semitone" uses the best integer approximation: round `pitch / $155` to the nearest integer, multiply by $155; equivalently, `snapped = (pitch + $AB) / $155 × $155`. Because $155 is an approximation of 4096/12, accumulated rounding across many octaves will drift by up to a few cents; this is documented behaviour and intentional given the microtonal grid.
+
+**Implementation.** Maintain a per-channel boolean `glissando_on`. When G updates `pitch`, if `glissando_on` is set, compute `display_pitch = round(pitch × 12 / 4096) × 4096 / 12` (using integer division with rounding) and send `display_pitch` to the mixer; otherwise send `pitch` directly.
+
+---
+
+## S $2x00 — Set fine-tune
+
+**Plain.** Overrides the current note's fine-tune by applying a fixed 4096-TET offset. The index `$x` selects one of sixteen predefined pitch offsets, following ScreamTracker 3's Hz-based fine-tune table but expressed directly in Taud units. This command is implemented for ST3 compatibility.
+
+**Compatibility.** The index scheme matches ST3 exactly: `$8` is the baseline (no change), `$0..$7` are progressively flatter, `$9..$F` are progressively sharper. The Hz reference values come from the ST3 User's Manual and are reproduced here for auditability; the Taud offset is `log2(Hz / 8363) × 4096`, rounded to the nearest integer. **Format converters are advised to apply offset to the note value directly.**
+
+| $x | Reference Hz | Taud offset |
+|---|---|---|
+| $0 | 7895 | −$0154 |
+| $1 | 7941 | −$0132 |
+| $2 | 7985 | −$0111 |
+| $3 | 8046 | −$00E4 |
+| $4 | 8107 | −$00B8 |
+| $5 | 8169 | −$008B |
+| $6 | 8232 | −$005D |
+| $7 | 8280 | −$003B |
+| $8 | 8363 | $0000 |
+| $9 | 8413 | +$0023 |
+| $A | 8463 | +$0046 |
+| $B | 8529 | +$0074 |
+| $C | 8581 | +$0098 |
+| $D | 8651 | +$00C8 |
+| $E | 8723 | +$00F9 |
+| $F | 8757 | +$0110 |
+
+ProTracker `E5x` maps to Taud `S $2x00` with the same index meaning.
+
+**Implementation.** On the row, look up the offset from the table and add it to the channel's base pitch before any other per-tick effect processes. The offset persists until another S $2x command or a note-reset event.
+
+---
+
+## S $3x00 — Vibrato LFO waveform
+
+**Plain.** Selects the shape of the vibrato (H and U) oscillator.
+
+| $x | Waveform | Retrigger on new note? |
+|---|---|---|
+| $0 | Sine | Yes |
+| $1 | Ramp down (sawtooth) | Yes |
+| $2 | Square | Yes |
+| $3 | Random | Yes |
+| $4 | Sine | No |
+| $5 | Ramp down | No |
+| $6 | Square | No |
+| $7 | Random | No |
+
+**Compatibility.** ST3 `S3x` and ProTracker `E4x` maps directly.
+
+**Implementation.** Store `vibrato_waveform = $x & $3` and `vibrato_retrigger = (($x & $4) == 0)` for the channel. The ramp-down shape is `$7F − ((pos & $3F) << 2)` across one logical cycle; the square shape is `sign(sine(pos)) × $7F`; random draws a fresh `rand() & $FF − $80` every tick. On a new note, if `vibrato_retrigger` is true, reset `lfo_pos = 0`.
+
+---
+
+## S $4x00 — Tremolo LFO waveform
+
+**Plain.** Selects the shape of the tremolo (R) oscillator; value encoding is identical to S $3x.
+
+**Compatibility.** ST3 `S4x` and ProTracker `E7x` maps directly.
+
+**Implementation.** As for S $3x, but applied to R's separate state (`tremolo_waveform`, `tremolo_retrigger`, and tremolo `lfo_pos`).
+
+---
+
+## S $5x00 — Panbrello LFO waveform
+
+**Plain.** Selects the shape of the panbrello (Y) oscillator; value encoding is identical to S $3x.
+
+**Compatibility.** IT `S5x` maps directly.
+
+**Implementation.** As for S $3x, but applied to Y's separate state (`panbrello_waveform`, `panbrello_retrigger`, and panbrello `lfo_pos`).
+
+---
+
+## S $6x00 — Fine pattern delay
+
+**Plain.** Extends the current row by $x ticks. If multiple S6x commands are on the same row, the sum of their parameters is used.
+
+**Compatibility.** IT `S6x` maps directly.
+
+**Implementation.** Maintain a per-row accumulator `fine_delay_extra` on the tracker state, initialised to 0 at the start of every row parse (including pattern-delay repetitions caused by S $Ex). Each S $6x command encountered during the row scan adds `$x` to `fine_delay_extra`. The row then runs for `speed + fine_delay_extra` ticks instead of the usual `speed` ticks before advancing to the next row.
+
+```
+on row parse (S $6x):
+    fine_delay_extra += x       # sum across all channels
+
+row ends when:
+    tick_in_row >= ticks_per_row + fine_delay_extra
+```
+
+S $6x and S $Ex are orthogonal: when S $Ex is active the current row repeats `$x` additional times, and each repetition is itself extended by `fine_delay_extra` (re-accumulated from the same row's S $6x commands). There is no memory for S $6x; `$x == 0` is a no-op.
+
+---
+
+## S $7x00 — Note/Instrument actions
+
+**Plain.** Performs following action to the note.
+
+| $x | Operation | Description |
+|---|---|---|
+| $0 | Past Note Cut | Cuts all notes playing as a result of New Note Actions on the current channel |
+| $1 | Past Note Off | Sends a Note Off to all notes playing as a result of New Note Actions on the current channel |
+| $2 | Past Note Fade | Fades out all notes playing as a result of New Note Actions on the current channel |
+| $3 | NNA Note Cut | Sets the currently active note's New Note Action to Note Cut |
+| $4 | NNA Note Continue | Sets the currently active note's New Note Action to Continue |
+| $5 | NNA Note Off | Sets the currently active note's New Note Action to Note Off |
+| $6 | NNA Note Fade | Sets the currently active note's New Note Action to Note Fade |
+| $7 | Volume Envelope Off | Disables the currently active note's volume envelope |
+| $8 | Volume Envelope On | Enables the currently active note's volume envelope |
+| $9 | Panning Envelope Off | Disables the currently active note's panning envelope |
+| $A | Panning Envelope On | Enables the currently active note's panning envelope |
+| $B | Pitch Envelope Off | Disables the currently active note's pitch or filter envelope |
+| $C | Pitch Envelope On | Enables the currently active note's pitch envelope  |
+
+**Compatibility.** IT `S7x` maps directly.
+
+**Implementation.** Engines maintain a *mixer-private* background-voice pool per playhead, separate from the addressable foreground voices. When a fresh note retriggers a still-active foreground voice, the engine reads the effective NNA — the per-voice override set by `S $73..$76` if present, otherwise the instrument's default NNA (instrument record byte 186, low two bits) — and acts on the displaced voice as follows:
+
+- **Note Cut (1):** discard the foreground state in place; no ghost is created.
+- **Note Off (0):** clone the foreground voice into the background pool and set its key-off flag, releasing any sustain loop. The clone's volume envelope plays out and fadeout decays from full.
+- **Continue (2):** clone the foreground voice into the background pool unchanged; envelopes and sample position continue from where they were.
+- **Note Fade (3):** clone the foreground voice into the background pool and immediately begin fadeout decay without releasing sustain. The volume envelope keeps looping its sustain region while fadeoutVolume drains to zero.
+
+Note Fade and Note Off are distinct: Note Fade does **not** set key-off, so the volume envelope's sustain loop continues to cycle; Note Off does set key-off, breaking sustain. Both share the same fadeout slope (`volumeFadeoutLow + (fadeoutHigh & 0x0F << 8)` units per tick out of 1024).
+
+The background pool is reaped when a ghost's `fadeoutVolume` drops to zero or its sample finishes (non-looping). Pool size is implementation-defined; the reference engine caps it at 64 ghosts per playhead and evicts the oldest on overflow. Background voices receive only passive per-tick maintenance (envelope advance, fadeout decay, auto-vibrato, filter coefficient refresh) — no row-driven effects (vibrato/tremolo/arpeggio/Q-retrigger/cut/delay) ever target them, since they are not addressable from the pattern.
+
+`S $70..$72` (Past Note Cut/Off/Fade) operate on every ghost whose `sourceChannel` matches the issuing channel: $70 drops them outright, $71 sets key-off on each, $72 begins fadeout on each.
+
+`S $73..$76` write the per-voice NNA override on the **currently active foreground voice** so that *its* next NNA event uses the overridden action. The override is cleared on every fresh trigger.
+
+`S $77..$7C` toggle the volume / panning / pitch-or-filter envelope on the currently active voice. While disabled, the envelope is frozen (no advancement) and the mixer treats its contribution as unity (envVolume / envPan / envPfValue all replaced by the neutral 1.0 / 0.5 / 0.5).
+
+---
+
+## S $80xx — Set channel pan position
+
+**Plain.** Sets the channel pan to `$xx`, with $00 being full left and $FF being full right. $80 is centre. When this command and panning column's Set Pan are both present, this command takes precedence.
+
+**Compatibility.** IT `Xxx` maps directly. ST3 `S8x` uses a 4-bit value.  
+1. convert by nibble-repeat: ST3 `S83` → Taud `S $8033`. Panning column command `0.$xx` has the same semantics and is the preferred form when a pan column is available in the pattern. ProTracker `8xx` (fine pan) and `E8x` (coarse pan) both map into Taud's 8-bit pan — the ProTracker 8-bit form maps directly; the 4-bit form nibble-repeats.
+2. convert to PanEff: ST3 `S8x` → PanEff `0.yy`, where `yy = round(4.2 * x)`
+
+**Implementation.** Write `channel_pan = arg & $FF`. The pan value is applied at the mixer: `left_gain = (($FF − pan) × $100) >> 8`, `right_gain = (pan × $100) >> 8`, with both applied before the global volume stage.
+
+---
+
+## S $Bx00 — Pattern loop
+
+**Plain.** Sets a loop point and loops within a pattern. `S $B000` marks the current row as the loop start (per channel, not per song); `S $Bx00` with $x > 0 returns playback to the saved row and plays the intervening range `$x` more times (so `$B200` plays the loop twice total beyond the initial pass).
+
+**Compatibility.** ST3 `SBx` maps directly. ProTracker `E6x` maps to Taud `S $Bx00`.
+
+ST3 has a long-documented bug where pattern delay (SEx) inside a pattern-loop range causes the loop counter to decrement multiple times per visit, producing unintended behaviour. **Taud fixes this bug.** On import, ST3 songs that relied on the bug will loop fewer times in Taud. Converters that want bit-exact ST3 playback should emit a warning when SBx and SEx appear in the same channel within a loop range, or optionally flatten loops by duplicating rows.
+
+**Implementation.** State per channel: `loop_start_row` (defaulting to 0 at each pattern entry) and `loop_count` (defaulting to 0).
+
+```
+on row event (S $Bx00):
+    x = (arg >> 8) & $0F
+    if x == 0:
+        loop_start_row = current_row
+    else:
+        if loop_count == 0:
+            loop_count = x
+            jump next_row -> loop_start_row
+        else:
+            loop_count -= 1
+            if loop_count > 0:
+                jump next_row -> loop_start_row
+            # else loop_count hits 0 on its own; fall through to next row
+
+on pattern change: loop_start_row = 0; loop_count = 0
+```
+
+The crucial bug fix relative to ST3: the loop-counter decrement happens **once per actual row playback**, not once per tick-0 invocation. When SBx shares a row with SEx (pattern delay), the pattern-delay machinery replays the row as a unit, but the SBx state machine treats the whole delay group as a single visit. Implement this by gating the SBx decrement on `pattern_delay_repetition == 0`.
+
+---
+
+## S $Cx00 — Note cut in $x ticks
+
+**Plain.** Silences the note on tick `$x` of the current row by forcing the channel's output volume to 0. The sample continues running internally, so a later volume-change or retrigger event can resume audio.
+
+**Compatibility.** ST3 `SCx` maps directly. ProTracker `ECx` also maps directly. ST3 ignores `SC0` (treats it as no cut at all); Taud preserves this.
+
+**Implementation.** On tick `$x`, set `output_volume = 0` but leave `base_volume` unchanged. If `$x ≥ speed`, the cut never fires. If `$x == 0`, the command is ignored. Set the `note_was_cut` flag so a later Q retrigger on the same row is suppressed.
+
+---
+
+## S $Dx00 — Note delay for $x ticks
+
+**Plain.** Delays the triggering of the note (and any co-row instrument, offset, and volume event) until tick `$x`. Until then, any currently playing note continues.
+
+**Compatibility.** ST3 `SDx` maps directly. ProTracker `EDx` also maps directly. `SD0` plays the note normally on tick 0. If `$x ≥ speed`, the note never plays on this row and does not carry over to the next row. Some trackers allow playback of "malformed" note delays (`$x` greater than current tick speed). Taud discards those notes. If such note events have been encountered during conversion, they must be corrected on the converter.
+
+**Implementation.** On row parse, defer the note-trigger event (including sample selection, volume, offset, and any volume-column effect) until tick `$x`. On tick `$x`, execute the deferred trigger. When combined with pattern delay (S $Ex00), the deferred trigger re-fires at the start of each row repetition — matching ST3's `kRowDelayWithNoteDelay` behaviour. If `$x` is greater than current tick speed, the note must be discarded (see compatibility notes above)
+
+---
+
+## S $Ex00 — Pattern delay for $x row-repeats
+
+**Plain.** Repeats the current row `$x` additional times (so `$x = 0` means no repeat and the row plays once; `$x = 3` means the row plays four times total). Notes do not retrigger across repetitions, but per-tick effects re-run and tick-0 events (fine slides, delayed notes) re-fire on each repetition.
+
+**Compatibility.** ST3 `SEx` maps directly. ProTracker `EEx` also maps directly. Simultaneous SEx on multiple channels: ST3 uses the first SEx in **pan order** (L1..L8 then R1..R8); **Taud uses the first SEx in ascending channel-index order** for predictability. Converters that encounter ST3 songs relying on the pan-order rule should emit a warning.
+
+Q retrigger counters do **not** reset between SEx repetitions.
+
+**Implementation.** Row duration becomes `speed × (1 + arg_x)` ticks. Treat each repetition as a fresh row for tick-0 purposes (so fine slides, delayed notes, and the like re-trigger), but do not reset arpeggio, vibrato, or tremolo LFO positions, and do not decrement SBx's loop counter more than once across the whole delay block.
+
+---
+
+## S $Fxxx — Funk repeat with speed $xxx (non-destructive)
+
+**Plain.** Produces a hiss-like progressive inversion of the sample loop, toggling individual bytes over time for a gritty textural effect. Setting `$x = 0` turns the effect off; higher `$x` advances the inversion faster.
+
+**Compatibility.** ProTracker `EFx` is destructive — it XORs bytes directly in the sample data, permanently corrupting the sample. **Taud's implementation is non-destructive**: the XOR is applied at playback time through a per-instrument bit-mask, leaving source samples pristine. ST3 does not implement SFx at all and will parse Taud's S $Fx00 as a no-op; converters targeting ST3 should drop the effect. ProTracker `EFx` imports as Taud `S $Fyyy`, where `yyy = funk_table[x]`.
+
+**Implementation.** Each instrument carries a `funk_mask` bit array, one bit per byte of the loop region, all zero at song start. A per-channel counter `funk_accumulator` and a per-channel `funk_write_pos` track progress.
+
+```
+funk_table[16] = { 0, 5, 6, 7, 8, $A, $B, $D, $10, $13, $16, $1A, $20, $2B, $40, $80 }
+
+on every tick (when S $Fxxxx is active with x != 0):
+    funk_accumulator += funk_length
+    while funk_accumulator >= $80:
+        funk_accumulator -= $80
+        bit = funk_mask[funk_write_pos]
+        funk_mask[funk_write_pos] = bit XOR 1
+        funk_write_pos = (funk_write_pos + 1) mod loop_length
+
+on sample byte read during loop playback:
+    raw_byte = sample_data[offset_in_loop]
+    if funk_mask[offset_in_loop] == 1:
+        output_byte = raw_byte XOR $FF
+    else:
+        output_byte = raw_byte
+```
+
+`S $F000` clears `funk_accumulator` but leaves `funk_mask` intact (so the accumulated inversion pattern persists until the instrument is reset). On a fresh note or instrument-change event, Taud optionally resets `funk_mask` to all zero; this is a per-implementation choice, but the recommended default is **reset on instrument-change, preserve on pure note retrigger**.
+
+---
+
+# Volume column effects
+
+Each cell carries a 6-bit value field plus a 2-bit selector field for the volume column. The four selectors are:
+
+- **`0.$xx` — Set volume** to `$xx` (6-bit, $00..$3F). Equivalent to a note's default volume.
+- **`1.$xx` — Volume slide up** by `$xx` per non-first tick (4-bit). Volume clamps at $3F.
+- **`2.$xx` — Volume slide down** by `$xx` per non-first tick (4-bit). Volume clamps at $00.
+- **`3.$Sx` — Fine volume slide** on tick 0 only. The high bit `$S` of the value selects direction (0 = down, 1 = up); the low 4 bits `$x` ($0..$F) are the magnitude. Equivalent in scale to `D $xF00` / `D $Fy00` but with a 5-bit cap. Fires once per row regardless of speed.
+
+Volume-column effects do not consume the main effect slot; a cell can carry both (for instance, a tone portamento in the effect slot and a volume slide in the volume column).
+
+When the converter folds an ST3 K, L, M, or N effect into the volume column, the slide-up / slide-down nibbles map to selectors 1 / 2 (clamped to 6 bits — values above $3F clip).
+
+NOTE: **`3.00` — is No-op**
+
+---
+
+# Panning column effects
+
+The panning column uses the same 6-bit value + 2-bit selector layout:
+
+- **`0.$xx` — Set pan** (6-bit, $00..$3F mapped onto the channel's 8-bit pan space; $01 = full left, $1F = centre-left, $20 = centre-right, $3F = full right). For 8-bit precision use `S $80xx` instead.
+- **`1.$xx` — Pan slide right** by `$xx` per non-first tick (4-bit).
+- **`2.$xx` — Pan slide left** by `$xx` per non-first tick (4-bit).
+- **`3.$Sx` — Fine pan slide** on tick 0 only, same direction-bit encoding as the volume column's selector 3.
+
+NOTE: **`3.00` — is No-op**. When Set Pan and S $80xx are both present, S-command takes precedence.
+
+---
+
+# Effects That Modifies Global Behaviour
+
+Effects in this section modifies the behaviour of the mixer. Primary intention of the commands is to provide switches for legacy tracker and modern DAW behaviours.
+
+## 1 $xx00 — Global behaviour flags
+
+**Plain.** Sets how the mixer should treat the panning. Available flags are:
+
+    0b 0000 00fp
+
+- p unset: Linear panning mode (tracker-accurate). Centre panning gets 3 dB boost. Default setting.
+- p set: Equal-power panning mode. L/R amplitude is at 0.707 when centre-panned.
+
+- f unset: Linear tone mode. Pitch shift will behave like MIDI/ImpulseTracker/ScreamTracker linear mode. **Coarse and fine E/F arguments are stored as 4096-TET pitch units** and subtracted/added directly from the stored pitch.
+- f set: Amiga (cycle-based) tone mode. Pitch shift will behave like ProTracker/ScreamTracker default mode. **Coarse and fine E/F arguments are stored as raw tracker period units** (the unscaled byte/nibble from the source PT/S3M/IT file) and applied in Amiga period space. Tone portamento (G) remains linear regardless of mode.
+
+**Implementation.**
+- Panning-linear: 
+  - L_gain = if (pan < 0x80) 1.0 else 1.0 - (pan - 128.0) / 128.0
+  - R_gain = if (pan < 0x80) pan / 128.0 else 1.0
+- Panning-equal-power:
+  - L_gain = cos(pi*x / 512.0)
+  - R_gain = sin(pi*x / 512.0)
+- Amiga tone (both coarse and fine E/F pitch slides). The `slideArg` is a **raw tracker period-unit count** (no scaling), with sign matching linear mode (negative for E, positive for F). Coarse slides apply on every non-first tick; fine slides apply once on tick 0 — the per-step arithmetic is identical:
+  - AMIGA_BASE_PERIOD = 428.0  (period at the Taud reference pitch C4 for a standard 8363 Hz instrument, NTSC clock — identical to PT "C-2" period 428)
+  - period = AMIGA_BASE_PERIOD × 2^(−(noteVal − C4) / 4096)
+  - period_new = period − slideArg                     (E subtracts pitch ⇒ adds period; F adds pitch ⇒ subtracts period)
+  - noteVal_new = C4 + 4096 × log2(AMIGA_BASE_PERIOD / period_new)
+
+**Initialisation from the song table.** The same flags byte is stored in the song-table entry (see file format §Song Table). A Taud player should write this byte to MMIO playhead register 7 before starting playback; the mixer then applies it as the initial state on every reset, and subsequent in-pattern `1` effects may override it.
+
+---
+
+# ProTracker to Taud conversion table
+
+This table maps each PT effect to its Taud equivalent. Arguments follow PT's two-nibble form and expand to Taud's 16-bit form as shown.
+
+| PT effect | Taud effect | Notes |
+|---------|-----------|-------|
+| `0 $xy` | `J $xxyy` | Arpeggio; nibble-repeat each byte. See the 12-TET → Taud table above for conversion losses |
+| `1 $xx` | `F $00xx` (Amiga mode, `f` set) | Portamento up; raw PT period units, applied in period space |
+| `2 $xx` | `E $00xx` (Amiga mode, `f` set) | Portamento down; raw PT period units, applied in period space |
+| `3 $xx` | `G round($0xxx × 64/3)` | Portamento to note; G is always linear (4096-TET units) regardless of mode |
+| `4 $xy` | `H $xxyy` | Vibrato; nibble-repeat each byte. |
+| `5 $xy` | `L $xy00` | Combined portamento + volume slide (see compatibility note) |
+| `6 $xy` | `K $xy00` | Combined vibrato + volume slide (see compatibility note) |
+| `7 $xy` | `R $xxyy` | Tremolo; nibble-repeat |
+| `8 $xx` | `S $80xx` or panning column `0.$xx` | Fine pan |
+| `9 $xx` | `O $xx00` | Sample offset |
+| `A $xy` | Volume column `1.$xy` | Volume slide |
+| `B $xx` | `B $00xx` | Position jump |
+| `C $xx` | Volume column `0.$xx` | Set volume |
+| `D $xx` | `C $00xx` (after BCD decode) | Pattern break |
+| `E $0x` | `S $000x` | (UNIMPLEMENTED) Set filter |
+| `E $1x` | `F $F00x` (Amiga mode, `f` set) | Fine pitch slide up; raw PT period units, applied in period space at tick 0 |
+| `E $2x` | `E $F00x` (Amiga mode, `f` set) | Fine pitch slide down; raw PT period units, applied in period space at tick 0 |
+| `E $3x` | `S $1x00` | Glissando control |
+| `E $4x` | `S $3x00` | Vibrato waveform |
+| `E $5x` | `S $2x00` | Set fine-tune |
+| `E $6x` | `S $Bx00` | Pattern loop |
+| `E $7x` | `S $4x00` | Tremolo waveform |
+| `E $8x` | `S $80xx` or panning column `0.$xx` | Coarse pan (nibble-repeat) |
+| `E $9x` | `Q $0x00` | Retrigger |
+| `E $Ax` | Volume column `3.$1x` | Fine volume slide up |
+| `E $Bx` | Volume column `3.$0x` | Fine volume slide down |
+| `E $Cx` | `S $Cx00` | Note cut |
+| `E $Dx` | `S $Dx00` | Note delay |
+| `E $Ex` | `S $Ex00` | Pattern delay |
+| `E $Fx` | `S $Fx00` | Funk repeat |
+| `F $xx` (xx < $20) | `A $xx00` | Set speed |
+| `F $xx` (xx ≥ $20) | `T $(xx−$18)00` | Set tempo |
+
+---
+
+# ScreamTracker 3 conversion notes
+
+These quirks of ST3 are worth preserving or flagging when importing S3M files into Taud:
+
+**Shared memory across effects.** In ST3, a single memory slot backs D, E, F, I, J, K, L, Q, R, and S. A `$00` argument on any of these recalls whichever effect last wrote a non-zero argument. Taud narrows this to four cohorts (EF / G / HU / R) plus private slots. The converter must **eagerly resolve ST3 recalls** — walking the pattern in playback order, tracking the shared memory value, and emitting explicit Taud arguments wherever an ST3 recall crosses a cohort boundary. Otherwise a Taud player will either recall the wrong value or recall $0000.
+
+**Cxx BCD encoding.** ST3 stores pattern-break row numbers as BCD on disk (`$10` means decimal 10). Taud uses binary. Decode on import; encode on export. Out-of-range BCD bytes (decimal 64 or higher) clamp to row 0.
+
+**Tempo range.** ST3 accepts tempos $20..$FF (BPM 32..255); Taud accepts bytes $00..$FF (BPM 24..279). Imported ST3 tempos must be shifted down by $18; Taud tempos below $08 and above $E7 cannot be represented in ST3 and should clamp on export.
+
+**SBx + SEx interaction.** ST3 miscounts loop iterations when pattern delay is active inside a pattern loop; Taud fixes this. Songs that depended on the bug for their intended playback will loop fewer times in Taud. Flag such songs on import.
+
+**Simultaneous SEx priority.** ST3 uses pan order (L1..L8, R1..R8); Taud uses ascending channel-index order. Rare; flag on import if multiple channels carry SEx in the same row.
+
+**Muted channels.** ST3 skips all effect processing on muted channels (no volume change, no tempo change, no jumps); Taud follows this rule for strict compatibility but recommends that new compositions avoid muting channels that carry global effects.
+
+**Volume cap.** ST3's volume caps at $40; Taud's at $3F. Notes that reached $40 in ST3 (a rare edge) will play marginally quieter in Taud.
+
+**Global volume scale.** ST3's 0..$40 maps to Taud's 0..$FF with a ×4 scale on import, truncated ÷4 on export.
+
+**Linear pitch slides.** ST3's slide arithmetic is period-based (Amiga) or linear-table-indexed; Taud carries both interpretations and selects between them via the song-table `f` flag. Conversion rules:
+
+- **ST3 linear mode** (`linear_slides` set in S3M flags): coarse forms (Exx/Fxx) use `round(× 64/3)` (1/16 semitone per ST3 unit); fine/extra-fine (EFx/EEx/FFx/FEx) use `round(× 16/3)` (1/64 semitone per ST3 unit). Taud `f` flag is **clear**; the engine subtracts the stored 4096-TET argument directly from the channel pitch.
+- **ST3 Amiga mode** (`linear_slides` clear): both coarse (Exx/Fxx) and fine/extra-fine (EFx/EEx/FFx/FEx) are stored **verbatim** as raw ST3 period units — coarse as `E/F $00xx`, fine as `E/F $F00x` — with no scaling. Taud `f` flag is **set**; the engine applies both forms in Amiga period space at playback, exactly recovering the source's period-step count and the non-linear pitch character.
+- G (tone portamento) is always converted with `round(× 64/3)` and treated as linear, regardless of mode.
+
+**Default tempo byte.** Taud's default $65 equals 125 BPM under the $18 offset; this is not the same as ST3's `$7D` default, which maps to Taud `$65` after subtracting $18. Converters must remap on both import and export.
+
+---
+
+End of reference.

assets/bios/tsvmbios.js

@@ -1,5 +1,5 @@
 con.reset_graphics();con.curs_set(0);con.clear();
-graphics.resetPalette();graphics.setBackground(0,0,0);
+graphics.resetPalette();graphics.setPalette(0, 0, 0, 0, 0);graphics.setBackground(0,0,0);
 
 let logo = gzip.decomp(base64.atob("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"));
 
@@ -77,7 +77,7 @@ tmr = sys.nanoTime();
 while (sys.nanoTime() - tmr < 2147483648) sys.spin();
 // clear screen
 graphics.clearPixels(255);con.color_pair(239,255);
-con.clear();con.move(1,1);
+con.clear();con.move(1,1);graphics.resetPalette();
 
 ///////////////////////////////////////////////////////////////////////////////
 

assets/disk0/AUTOEXEC.BAT

@@ -5,5 +5,6 @@ set PATH=\tvdos\installer;\tvdos\tuidev;$PATH
 set KEYBOARD=us_colemak
 
 rem this line specifies which shell to be presented after the boot precess:
+tvdos/i18n/korean
 zfm
 command -fancy

assets/disk0/home/hdk/compile.js

@@ -1,6 +1,6 @@
 if (exec_args[1] === undefined) {
     println("Usage: compile -le/-lo myfile.js")
-    println("    The compiled and linked file will be myfile.out")
+    println("    The compiled and linked file will be myfile.exc")
     return 1
 }
 
@@ -14,7 +14,7 @@ if (exec_args[2]) {
         _G.shell.execute(`rm ${tempFilename}.gz`)
 
         _G.shell.execute(`link -${exec_args[1][2]} ${tempFilename}.bin`)
-        _G.shell.execute(`mv ${tempFilename}.out ${filenameWithoutExt}.out`)
+        _G.shell.execute(`mv ${tempFilename}.exc ${filenameWithoutExt}.exc`)
         _G.shell.execute(`rm ${tempFilename}.bin`)
 }
 // with no linking

assets/disk0/home/hdk/decompile.js

@@ -1,6 +1,6 @@
 if (exec_args[1] === undefined) {
-    println("Usage: decompile myfile.bin")
-    println("The compiled file will be myfile.bin.js")
+    println("Usage: decompile myfile.exc")
+    println("The compiled file will be myfile.exc.js")
     return 1
 }
 _G.shell.execute(`enc ${exec_args[1]} ${exec_args[1]}.gz`)

assets/disk0/home/hdk/enc.js

@@ -1,3 +1,5 @@
+// a simple, symmetric obfuscator with infinite-length key
+
 function seq(s) {
     let out = ""
     let cnt = 0

assets/disk0/home/hdk/link.js

@@ -11,7 +11,6 @@ let infile = files.open(infilePath)
 
 if (!infile.exists) throw Error("No such file: " + infilePath)
 
-let outfile = files.open(infilePath.substringBeforeLast(".") + ".out")
 let outMode = exec_args[1].toLowerCase()
 
 let type = {
@@ -21,6 +20,13 @@ let type = {
     "-c": "\x04"
 }
 
+let ext = {
+    "-r": ".exc", // executable
+    "-e": ".exc", // executable
+    "-o": ".lib", // library
+    "-c": ".cob"  // core object
+}
+
 function toI32(num) {
     const buffer = new ArrayBuffer(4)
     const view = new DataView(buffer)
@@ -40,6 +46,7 @@ let addr = 0
 if (exec_args[3] !== undefined && exec_args[3].toLowerCase() == "-a" && exec_args[4] !== undefined)
     addr = parseInt(exec_args[4], 16)
 
+let outfile = files.open(infilePath.substringBeforeLast(".") + ext[exec_args[3].toLowerCase()])
 outfile.sappend("\x20\xC0\xCC\x0A")
 outfile.sappend(type[outMode] || "\x00")
 outfile.bappend(toI24(addr))

assets/disk0/home/hdk/load.js

@@ -1,5 +1,5 @@
 if (exec_args[1] === undefined) {
-    println("Usage: load myfile.out")
+    println("Usage: load myfile.exc")
     println("   This will load the binary image onto the Core Memory")
     return 1
 }

assets/disk0/home/playrawpcm.js

@@ -4,7 +4,7 @@ music.pread(samples, 65534)
 
 audio.setPcmMode(0)
 audio.setMasterVolume(0, 255)
-audio.putPcmDataByPtr(samples, 65534, 0)
+audio.putPcmDataByPtr(0, samples, 65534, 0)
 audio.setLoopPoint(0, 65534)
 audio.play(0)*/
 
@@ -127,7 +127,7 @@ while (sampleSize > 0) {
             let readLength = (sampleSize < BLOCK_SIZE) ? sampleSize : BLOCK_SIZE
             readBytes(readLength, decodePtr)
 
-            audio.putPcmDataByPtr(decodePtr, readLength, 0)
+            audio.putPcmDataByPtr(0, decodePtr, readLength, 0)
             audio.setSampleUploadLength(0, readLength)
             audio.startSampleUpload(0)
 

assets/disk0/tracker_play.js

@@ -0,0 +1,21 @@
+const taud = require("taud")
+
+const fullFilePath = _G.shell.resolvePathInput(exec_args[1])
+if (fullFilePath === undefined) {
+    println(`Usage: ${exec_args[0]} path_to.taud`)
+    return 1
+}
+
+const PLAYHEAD = 0
+
+println("Playing "+fullFilePath.full)
+
+audio.resetParams(PLAYHEAD)
+audio.purgeQueue(PLAYHEAD)
+audio.stop(PLAYHEAD)
+
+taud.uploadTaudFile(fullFilePath.full, 0, PLAYHEAD)
+audio.setMasterVolume(PLAYHEAD, 255)
+audio.setMasterPan(PLAYHEAD, 128)
+audio.setCuePosition(PLAYHEAD, 0)
+audio.play(PLAYHEAD)

assets/disk0/tracker_test.js

@@ -0,0 +1,186 @@
+// Tracker Mode — Bach's Prelude in C Major (BWV 846)
+// Run from the TVDOS shell: js tracker_test.js
+// Uploads ~92 patterns on startup (takes a moment).
+
+// -- Note table (12-TET, 4096-TET encoding) ------------------------------------
+// C3 = 0x4000; each semitone = 4096/12 ≈ 341.33 steps; each octave = 4096 steps.
+// Sharp suffix: s (e.g. Cs3); flat aliases also provided (e.g. Db3 = Cs3).
+// Special values: Note.OFF = key-off, Note.CUT = note cut, Note.NOP = no-op.
+var Note = (function() {
+    var SEMITONE = 4096 / 12;
+    var C3 = 0x4000;
+    function n(oct, semi) { return Math.round(C3 + (oct - 3) * 4096 + semi * SEMITONE) & 0xFFFF; }
+    var t = {};
+    var names = ['C','Cs','D','Ds','E','F','Fs','G','Gs','A','As','B'];
+    var flats  = ['C','Db','D','Eb','E','F','Gb','G','Ab','A','Bb','B'];
+    for (var oct = 0; oct <= 9; oct++) {
+        for (var s = 0; s < 12; s++) {
+            t[names[s] + oct] = n(oct, s);
+            if (flats[s] !== names[s]) t[flats[s] + oct] = n(oct, s);
+        }
+    }
+    t.OFF = 0x0000;   // key-off
+    t.CUT = 0xFFFE;   // note cut (immediate)
+    t.NOP = 0xFFFF;   // no-op (empty row)
+    return t;
+}());
+
+var PLAYHEAD = 0;
+
+// -- 1. Sample: triangle wave (256 samples @ C3) --------------------------------
+var SAMPLE_LEN = 256;
+var sampleBytes = new Array(SAMPLE_LEN);
+for (var i = 0; i < SAMPLE_LEN; i++) {
+    var phase = (i / SAMPLE_LEN) * 2.0;
+    var val_ = phase < 1.0 ? phase : 2.0 - phase;
+    sampleBytes[i] = Math.round(val_ * 254) & 0xFF;
+}
+var memBase = audio.getMemAddr();
+for (var i = 0; i < SAMPLE_LEN; i++) {
+    sys.poke(memBase - i, sampleBytes[i]);
+}
+
+// -- 2. Instrument 0 -----------------------------------------------------------
+var instBytes = new Array(64).fill(0);
+instBytes[2] = 0; instBytes[3] = 1;        // sampleLength = 256
+instBytes[4] = 0x00; instBytes[5] = 0x7D;  // samplingRate = 32000
+instBytes[10] = 0x00; instBytes[11] = 0x01;  // sampleLoopEnd = 256 (whole sample)
+instBytes[12] = 1;                           // loopMode = 1 (forward)
+instBytes[16] = 255; instBytes[17] = 0;     // envelope: vol=255, hold
+audio.uploadInstrument(1, instBytes);
+
+// -- 3. Piano-roll builder -----------------------------------------------------
+// Source convention: C1=0, C2=12, C3=24, C4=36 (i.e. C3=24, octave every 12).
+function midiToTsvm(n) {
+    var oct = Math.floor(n / 12) + 1;
+    return Math.round(0x3000 + oct * 4096 + (n % 12) * (4096 / 12)) & 0xFFFF;
+}
+
+var noteMap = {};  // absRow → TSVM note value
+var rowCursor = 0;
+
+function seq(notes, lens) {
+    for (var i = 0; i < notes.length; i++) {
+        noteMap[rowCursor] = midiToTsvm(notes[i]);
+        rowCursor += lens[i];
+    }
+}
+
+var TD = 3;  // rows per note step (= source TICK_DIVISOR)
+
+function prel(n1, n2, n3, n4, n5) {
+    seq([n1, n2, n3, n4, n5, n3, n4, n5, n1, n2, n3, n4, n5, n3, n4, n5],
+        [TD+2, TD, TD, TD-1, TD, TD, TD, TD, TD, TD, TD, TD-1, TD, TD, TD, TD]);
+}
+function end1(n1,n2,n3,n4,n5,n6,n7,n8,n9) {
+    seq([n1, n2, n3, n4, n5, n6, n5, n4, n5, n7, n8, n7, n8, n9, n8, n9],
+        [TD+2, TD, TD, TD-1, TD, TD, TD, TD, TD, TD, TD, TD-1, TD, TD, TD, TD]);
+}
+function end2(n1,n2,n3,n4,n5,n6,n7,n8,n9) {
+    seq([n1, n2, n3, n4, n5, n6, n5, n4, n5, n4, n3, n4, n7, n8, n9, n7],
+        [TD+2, TD+1, TD+1, TD+1, TD+1, TD+2, TD+2, TD+2,
+         TD+3, TD+3, TD+4, TD+4, TD+6, TD+8, TD+12, TD+24]);
+}
+function end3(ns) {
+    for (var i = 0; i < ns.length; i++) {
+        noteMap[rowCursor] = midiToTsvm(ns[i]);
+        rowCursor += 1;
+    }
+    for (var i = 0; i < TD*2; i++) {
+        noteMap[rowCursor] = Note.NOP
+        rowCursor += 1;
+    }
+}
+
+// -- 4. Build the piece --------------------------------------------------------
+rowCursor = 16 * TD;  // 160-row intro silence
+
+prel(24,28,31,36,40);
+prel(24,26,33,38,41);
+prel(23,26,31,38,41);
+prel(24,28,31,36,40);
+prel(24,28,33,40,45);
+prel(24,26,30,33,38);
+prel(23,26,31,38,43);
+prel(23,24,28,31,36);
+prel(21,24,28,31,36);
+prel(14,21,26,30,36);
+prel(19,23,26,31,35);
+prel(19,22,28,31,37);
+prel(17,21,26,33,38);
+prel(17,20,26,29,35);
+prel(16,19,24,31,36);
+prel(16,17,21,24,29);
+prel(14,17,21,24,29);
+prel( 7,14,19,23,29);
+prel(12,16,19,24,28);
+prel(12,19,22,24,28);
+prel( 5,17,21,24,28);
+prel( 6,12,21,24,27);
+prel( 8,17,23,24,26);
+prel( 7,17,19,23,26);
+prel( 7,16,19,24,28);
+prel( 7,14,19,24,29);
+prel( 7,14,19,23,29);
+prel( 7,15,21,24,30);
+prel( 7,16,19,24,31);
+prel( 7,14,19,24,29);
+prel( 7,14,19,23,29);
+prel( 0,12,19,22,28);
+end1( 0,12,17,21,24,29,21,17,14);
+end2( 0,11,31,35,38,41,26,29,28);
+end3([0,12,28,31,36]);
+
+noteMap[rowCursor] = Note.OFF;    // key-off at start of final silence
+rowCursor += 16 * TD - 5;         // 155 more rows of silence
+
+var totalRows = rowCursor;         // 5836
+var NUM_ROWS = 64;
+var numPatterns = Math.ceil(totalRows / NUM_ROWS);  // 92
+
+// -- 5. Build and upload patterns ----------------------------------------------
+for (var p = 0; p < numPatterns; p++) {
+    var patBytes = new Array(512).fill(0);
+    for (var r = 0; r < NUM_ROWS; r++) {
+        var absRow = p * NUM_ROWS + r;
+        var noteVal = (noteMap[absRow] !== undefined) ? noteMap[absRow] : Note.NOP;
+        var isOn = (noteVal !== Note.NOP && noteVal !== Note.OFF && noteVal !== Note.CUT);
+        var off = r * 8;
+        patBytes[off]     = noteVal & 0xFF;
+        patBytes[off + 1] = (noteVal >> 8) & 0xFF;
+        patBytes[off + 2] = 1;              // instrument 1
+        patBytes[off + 3] = 63;  // volume
+        patBytes[off + 4] = 31;  // pan (centre)
+    }
+    audio.uploadPattern(p, patBytes);
+}
+
+// -- 6. Cue sheet: one entry per pattern, last halts -------------------------
+// Cue format: 32 bytes, 20 voices with 12-bit pattern numbers packed as:
+//   bytes 0-9:  low nybbles (byte i = voice i*2 in hi-nybble, voice i*2+1 in lo-nybble)
+//   bytes 10-19: mid nybbles (same packing)
+//   bytes 20-29: high nybbles (same packing)
+//   byte 30: instruction (0=NOP, 1=Halt)
+// Voice 0 plays pattern c; voices 1-19 are disabled (0xFFF).
+for (var c = 0; c < numPatterns; c++) {
+    var cueBytes = new Array(32).fill(0xFF);
+    // voice 0 = c (12-bit), voice 1 = 0xFFF → byte0=(c&0xF)<<4|0xF
+    cueBytes[0]  = ((c & 0xF) << 4) | 0xF;           // lo nybbles v0,v1
+    cueBytes[10] = (((c >> 4) & 0xF) << 4) | 0xF;    // mid nybbles v0,v1
+    cueBytes[20] = (((c >> 8) & 0xF) << 4) | 0xF;    // hi nybbles v0,v1
+    cueBytes[30] = (c === numPatterns - 1) ? 0x01 : 0;
+    audio.uploadCue(c, cueBytes);
+}
+
+// -- 7. Playback ---------------------------------------------------------------
+// BPM=500, tickRate=1: 1 row = 5 ms; 10 rows/step × 16 steps/bar ≈ 75 bars/min.
+audio.setTrackerMode(PLAYHEAD);
+audio.setBPM(PLAYHEAD, 250);
+audio.setTickRate(PLAYHEAD, 6);
+audio.setMasterVolume(PLAYHEAD, 255);
+audio.setMasterPan(PLAYHEAD, 128);
+audio.setCuePosition(PLAYHEAD, 0);
+audio.play(PLAYHEAD);
+
+println("Bach's Prelude in C Major -- " + numPatterns + " patterns loaded.");
+println("Stop: audio.stop(" + PLAYHEAD + ")");

assets/disk0/tvdos/TVDOS.SYS

@@ -147,7 +147,7 @@ _TVDOS.variables = {
     LANG: "EN",
     KEYBOARD: "us_qwerty",
     PATH: "\\tvdos\\bin;\\home",
-    PATHEXT: ".com;.bat;.app;.js",
+    PATHEXT: ".com;.bat;.app;.js;.alias",
     HELPPATH: "\\tvdos\\help",
     OS_NAME: "TSVM Disk Operating System",
     OS_VERSION: _TVDOS.VERSION
@@ -225,8 +225,9 @@ class TVDOSFileDescriptor {
     }
 
     /** reads the file bytewise and puts it to the specified memory address
-     * @param count optional -- how many bytes to read
-     * @param offset optional -- how many bytes to skip initially
+     * @param ptr -- where the bytes should be dumped
+     * @param count -- how many bytes to read
+     * @param offset -- how many bytes to skip initially from the file
      */
     pread(ptr, count, offset) {
         this.driver.pread(this, ptr, count, offset)
@@ -241,7 +242,9 @@ class TVDOSFileDescriptor {
     }
 
     /** writes the bytes stored in the memory[ptr .. ptr+count-1] to file[offset .. offset+count-1]
-     * - @param offset is optional
+     * @param ptr -- where the bytes are
+     * @param count -- how many bytes to write
+     * @param offset -- position in the file
      */
     pwrite(ptr, count, offset) {
         this.driver.pwrite(this, ptr, count, offset)
@@ -420,11 +423,11 @@ _TVDOS.DRV.FS.SERIAL.sread = (fd) => {
 }
 _TVDOS.DRV.FS.SERIAL.bread = (fd) => {
     let str = _TVDOS.DRV.FS.SERIAL.sread(fd)
-    let bytes = new Int8Array(str.length)
+    let bytes = []//new Int8Array(str.length)
     for (let i = 0; i < str.length; i++) {
 //        let p = str.charCodeAt(i)
 //        bytes[i] = (p > 127) ? p - 255 : p
-        bytes[i] = str.charCodeAt(i)
+        bytes.push(str.charCodeAt(i))
     }
     return bytes
 }
@@ -870,11 +873,21 @@ Object.freeze(_TVDOS.DRV.FS.DEVPT)
 _TVDOS.DRV.FS.DEVFBIPF = {}
 
 _TVDOS.DRV.FS.DEVFBIPF.pwrite = (fd, infilePtr, count, _2) => {
-    let decodefun = ([graphics.decodeIpf1, graphics.decodeIpf2])[sys.peek(infilePtr + 13)]
+    let flags = sys.peek(infilePtr+12)
+    let ipfType = sys.peek(infilePtr+13)
+    let isProgressive = (flags & 0x80) != 0
+    let hasAlpha = (flags & 0x01) != 0
+
+    // Select decode function based on type and progressive flag
+    let decodefun
+    if (isProgressive) {
+        decodefun = ([graphics.decodeIpf1Progressive, graphics.decodeIpf2Progressive])[ipfType]
+    } else {
+        decodefun = ([graphics.decodeIpf1, graphics.decodeIpf2])[ipfType]
+    }
+
     let width = sys.peek(infilePtr+8) | (sys.peek(infilePtr+9) << 8)
     let height = sys.peek(infilePtr+10) | (sys.peek(infilePtr+11) << 8)
-    let hasAlpha = (sys.peek(infilePtr+12) != 0)
-    let ipfType = sys.peek(infilePtr+13)
     let imgLen = sys.peek(infilePtr+24) | (sys.peek(infilePtr+25) << 8) | (sys.peek(infilePtr+26) << 16) | (sys.peek(infilePtr+27) << 24)
 
     let ipfbuf = sys.malloc(imgLen)
@@ -1014,136 +1027,6 @@ _TVDOS.DRV.FS.NET.exists = (fd) => {
     return (0 == com.getStatusCode(port[0]))
 }
 
-///////////////////////////////////////////////////////////////////////////////
-
-
-// Legacy Serial filesystem, !!pending for removal!!
-
-
-/*const filesystem = {};
-
-filesystem._toPorts = (driveLetter) => {
-    if (driveLetter.toUpperCase === undefined) {
-        throw Error("'"+driveLetter+"' (type: "+typeof driveLetter+") is not a valid drive letter");
-    }
-    var port = _TVDOS.DRIVES[driveLetter.toUpperCase()];
-    if (port === undefined) {
-        throw Error("Drive letter '" + driveLetter.toUpperCase() + "' does not exist");
-    }
-    return port
-};
-filesystem._close = (portNo) => {
-    com.sendMessage(portNo, "CLOSE")
-}
-filesystem._flush = (portNo) => {
-    com.sendMessage(portNo, "FLUSH")
-}
-
-// @return disk status code (0 for successful operation)
-//         throws if:
-//             - java.lang.NullPointerException if path is null
-//             - Error if operation mode is not "R", "W" nor "A"
-filesystem.open = (driveLetter, path, operationMode) => {
-    var port = filesystem._toPorts(driveLetter);
-
-    filesystem._flush(port[0]); filesystem._close(port[0]);
-
-    var mode = operationMode.toUpperCase();
-    if (mode != "R" && mode != "W" && mode != "A") {
-        throw Error("Unknown file opening mode: " + mode);
-    }
-
-    com.sendMessage(port[0], "OPEN"+mode+'"'+path+'",'+port[1]);
-    return com.getStatusCode(port[0]);
-};
-filesystem.getFileLen = (driveLetter) => {
-    var port = filesystem._toPorts(driveLetter);
-    com.sendMessage(port[0], "GETLEN");
-    var response = com.getStatusCode(port[0]);
-    if (135 == response) {
-        throw Error("File not opened");
-    }
-    if (response < 0 || response >= 128) {
-        throw Error("Reading a file failed with "+response);
-    }
-    return Number(com.pullMessage(port[0]));
-};
-// @return the entire contents of the file in String
-filesystem.readAll = (driveLetter) => {
-    var port = filesystem._toPorts(driveLetter);
-    com.sendMessage(port[0], "READ");
-    var response = com.getStatusCode(port[0]);
-    if (135 == response) {
-        throw Error("File not opened");
-    }
-    if (response < 0 || response >= 128) {
-        throw Error("Reading a file failed with "+response);
-    }
-    return com.pullMessage(port[0]);
-};
-filesystem.readAllBytes = (driveLetter) => {
-    var str = filesystem.readAll(driveLetter);
-    var bytes = new Uint8Array(str.length);
-    for (let i = 0; i < str.length; i++) {
-        bytes[i] = str.charCodeAt(i);
-    }
-    return bytes;
-};
-filesystem.write = (driveLetter, string) => {
-    var port = filesystem._toPorts(driveLetter);
-    com.sendMessage(port[0], "WRITE"+string.length);
-    var response = com.getStatusCode(port[0]);
-    if (135 == response) {
-        throw Error("File not opened");
-    }
-    if (response < 0 || response >= 128) {
-        throw Error("Writing a file failed with "+response);
-    }
-    com.sendMessage(port[0], string);
-    filesystem._flush(port[0]); filesystem._close(port[0]);
-};
-filesystem.writeBytes = (driveLetter, bytes) => {
-    var string = btostr(bytes); // no spreading: has length limit
-    filesystem.write(driveLetter, string);
-};
-filesystem.isDirectory = (driveLetter) => {
-    var port = filesystem._toPorts(driveLetter);
-    com.sendMessage(port[0], "LISTFILES");
-    var response = com.getStatusCode(port[0]);
-    return (response === 0);
-};
-filesystem.mkDir = (driveLetter) => {
-    var port = filesystem._toPorts(driveLetter);
-    com.sendMessage(port[0], "MKDIR");
-    var response = com.getStatusCode(port[0]);
-
-    if (response < 0 || response >= 128) {
-        var status = com.getDeviceStatus(port[0]);
-        throw Error("Creating a directory failed with ("+response+"): "+status.message+"\n");
-    }
-    return (response === 0); // possible status codes: 0 (success), 1 (fail)
-};
-filesystem.touch = (driveLetter) => {
-    var port = filesystem._toPorts(driveLetter);
-    com.sendMessage(port[0], "TOUCH");
-    var response = com.getStatusCode(port[0]);
-    return (response === 0);
-};
-filesystem.mkFile = (driveLetter) => {
-    var port = filesystem._toPorts(driveLetter);
-    com.sendMessage(port[0], "MKFILE");
-    var response = com.getStatusCode(port[0]);
-    return (response === 0);
-};
-filesystem.remove = (driveLetter) => {
-    var port = filesystem._toPorts(driveLetter);
-    com.sendMessage(port[0], "DELETE");
-    var response = com.getStatusCode(port[0]);
-    return (response === 0);
-};
-Object.freeze(filesystem);*/
-
-
 ///////////////////////////////////////////////////////////////////////////////
 
 const files = {}

assets/disk0/tvdos/bin/command.js

@@ -35,7 +35,7 @@ function print_prompt_text() {
         print(" "+CURRENT_DRIVE+":")
         con.color_pair(161,253)
         con.addch(16);con.curs_right()
-        con.color_pair(0,253)
+        con.color_pair(240,253)
         print(" \\"+shell_pwd.join("\\").substring(1)+" ")
         if (errorlevel != 0 && errorlevel != "undefined" && errorlevel != undefined) {
             con.color_pair(166,253)
@@ -61,7 +61,7 @@ function greet() {
         con.clear()
         con.color_pair(253,255)
         print('  ');con.addch(17);con.curs_right()
-        con.color_pair(0,253)
+        con.color_pair(240,253)
         print(" ".repeat(greetLeftPad)+welcome_text+" ".repeat(greetRightPad))
         con.color_pair(253,255)
         con.addch(16);con.curs_right();print('  ')
@@ -753,6 +753,25 @@ shell.execute = function(line) {
                         shell.execute(line)
                     })
                 }
+                else if ("ALIAS" == extension) {
+                    // parse alias
+                    // $0: all arguments
+                    // $1..9: specific arguments
+                    var lines = programCode.split('\n').filter(function(it) { return it.length > 0 }) // this return is not shell's return!
+                    lines.forEach(function(line) {
+                        var newLine = line
+
+                        // replace $1..$9
+                        for (let j = 1; j < 9; j++) {
+                            newLine = newLine.replaceAll('$'+j, tokens[j])
+                        }
+
+                        // replace $0
+                        newLine = newLine.replaceAll('$0', tokens.slice(1).join(' '))
+
+                        shell.execute(newLine)
+                    })
+                }
                 else if ("APP" == extension) {
                     let appexec = `A:${_TVDOS.variables.DOSDIR}\\sbin\\appexec.js`
                     let foundFile = searchFile.fullPath

assets/disk0/tvdos/bin/hopper.js

@@ -0,0 +1,5 @@
+/**
+ * Hopper is a package manager for TSVM
+ * Created by CuriousTorvald on 2026-04-16
+ */
+

assets/disk0/tvdos/bin/microtone.alias

@@ -0,0 +1 @@
+taut $0

assets/disk0/tvdos/bin/playmv1.js

@@ -326,7 +326,7 @@ while (!stopPlay && seqread.getReadCount() < FILE_LENGTH) {
                     // RAW PCM packets (decode on the fly)
                     else if (packetType == 0x1000 || packetType == 0x1001) {
                         let frame = seqread.readBytes(readLength)
-                        audio.putPcmDataByPtr(frame, readLength, 0)
+                        audio.putPcmDataByPtr(0, frame, readLength, 0)
                         audio.setSampleUploadLength(0, readLength)
                         audio.startSampleUpload(0)
                         sys.free(frame)

assets/disk0/tvdos/bin/playpcm.js

@@ -162,7 +162,7 @@ while (!stopPlay && seqread.getReadCount() < FILE_SIZE && readLength > 0) {
 
             seqread.readBytes(readLength, readPtr)
 
-            audio.putPcmDataByPtr(readPtr, readLength, 0)
+            audio.putPcmDataByPtr(0, readPtr, readLength, 0)
             audio.setSampleUploadLength(0, readLength)
             audio.startSampleUpload(0)
 

assets/disk0/tvdos/bin/playtav.js

@@ -9,6 +9,7 @@ const MAXMEM = sys.maxmem()
 const WIDTH = 560
 const HEIGHT = 448
 const TAV_MAGIC = [0x1F, 0x54, 0x53, 0x56, 0x4D, 0x54, 0x41, 0x56] // "\x1FTSVM TAV"
+const TAP_MAGIC = [0x1F, 0x54, 0x53, 0x56, 0x4D, 0x54, 0x41, 0x50] // "\x1FTSVM TAP"
 const UCF_MAGIC = [0x1F, 0x54, 0x53, 0x56, 0x4D, 0x55, 0x43, 0x46] // "\x1FTSVM UCF"
 const TAV_VERSION = 1  // Initial DWT version
 const UCF_VERSION = 1
@@ -17,6 +18,7 @@ const ADDRESSING_INTERNAL = 0x02
 const SND_BASE_ADDR = audio.getBaseAddr()
 const SND_MEM_ADDR = audio.getMemAddr()
 const pcm = require("pcm")
+const AUDIO_DEVICE = 0
 const MP2_FRAME_SIZE = [144,216,252,288,360,432,504,576,720,864,1008,1152,1440,1728]
 const TAV_TEMPORAL_LEVELS = 2
 
@@ -151,13 +153,10 @@ graphics.clearPixels4(0)
 const gpuGraphicsMode = graphics.getGraphicsMode()
 
 // Initialize audio
-audio.resetParams(0)
-audio.purgeQueue(0)
-audio.setPcmMode(0)
-audio.setMasterVolume(0, 255)
-
-// set colour zero as half-opaque black
-graphics.setPalette(0, 0, 0, 0, 7)
+audio.resetParams(AUDIO_DEVICE)
+audio.purgeQueue(AUDIO_DEVICE)
+audio.setPcmMode(AUDIO_DEVICE)
+audio.setMasterVolume(AUDIO_DEVICE, 255)
 
 // Parse SSF-TC subtitle packet and add to event buffer (0x31)
 function parseSubtitlePacketTC(packetSize) {
@@ -367,6 +366,8 @@ let header = {
     width: 0,
     height: 0,
     fps: 0,
+    fps_num: 0,           // Fractional FPS numerator (from XFPS or derived from fps)
+    fps_den: 1,           // Fractional FPS denominator (from XFPS, default 1)
     totalFrames: 0,
     waveletFilter: 0,     // TAV-specific: wavelet filter type
     decompLevels: 0,      // TAV-specific: decomposition levels
@@ -381,6 +382,22 @@ let header = {
     fileRole: 0
 }
 
+// Helper function to parse XFPS string ("num/den" format) and update header
+function parseXFPS(xfpsStr) {
+    let parts = xfpsStr.split("/")
+    if (parts.length === 2) {
+        let num = parseInt(parts[0], 10)
+        let den = parseInt(parts[1], 10)
+        if (!isNaN(num) && !isNaN(den) && den > 0) {
+            header.fps_num = num
+            header.fps_den = den
+            header.fps = num / den
+            return true
+        }
+    }
+    return false
+}
+
 // Read and validate header
 for (let i = 0; i < 8; i++) {
     header.magic[i] = seqread.readOneByte()
@@ -389,7 +406,7 @@ for (let i = 0; i < 8; i++) {
 // Validate magic number
 let magicValid = true
 for (let i = 0; i < 8; i++) {
-    if (header.magic[i] !== TAV_MAGIC[i]) {
+    if (header.magic[i] !== TAV_MAGIC[i] &&header.magic[i] !== TAP_MAGIC[i] ) {
         magicValid = false
         break
     }
@@ -401,10 +418,16 @@ if (!magicValid) {
     return
 }
 
+// Check if this is a TAP still image file (magic ends with 'P' instead of 'V')
+const isTapFile = (header.magic[7] === TAP_MAGIC[7])
+
 header.version = seqread.readOneByte()
 header.width = seqread.readShort()
 header.height = seqread.readShort()
 header.fps = seqread.readOneByte()
+// Set default fractional fps (will be overridden by XFPS if present)
+header.fps_num = header.fps
+header.fps_den = 1
 header.totalFrames = seqread.readInt()
 header.waveletFilter = seqread.readOneByte()
 header.decompLevels = seqread.readOneByte()
@@ -457,7 +480,7 @@ const isLossless = (header.videoFlags & 0x04) !== 0
 
 console.log(`TAV Decoder`)
 console.log(`Resolution: ${header.width}x${header.height}`)
-console.log(`FPS: ${header.fps}`)
+console.log(`FPS: ${header.fps === 255 ? "(see XFPS)" : header.fps}`)
 console.log(`Total frames: ${header.totalFrames}`)
 console.log(`Wavelet filter: ${header.waveletFilter === WAVELET_5_3_REVERSIBLE ? "5/3 reversible" : header.waveletFilter === WAVELET_9_7_IRREVERSIBLE ? "9/7 irreversible" : header.waveletFilter === WAVELET_BIORTHOGONAL_13_7 ? "Biorthogonal 13/7" : header.waveletFilter === WAVELET_DD4 ? "DD-4" : header.waveletFilter === WAVELET_HAAR ? "Haar" : "unknown"}`)
 console.log(`Decomposition levels: ${header.decompLevels}`)
@@ -469,6 +492,135 @@ console.log(`Features: ${hasAudio ? "Audio " : ""}${hasSubtitles ? "Subtitles "
 console.log(`Video flags raw: 0x${header.videoFlags.toString(16)}`)
 console.log(`Scan type: ${isInterlaced ? "Interlaced" : "Progressive"}`)
 
+// Handle TAP still image file
+if (isTapFile) {
+    console.log("TAP still image detected")
+
+    // Allocate single frame buffer for still image
+    const FRAME_PIXELS = header.width * header.height
+    const FRAME_SIZE = FRAME_PIXELS * 3
+
+    const RGB_BUFFER = sys.malloc(FRAME_SIZE)
+    const PREV_RGB_BUFFER = sys.malloc(FRAME_SIZE)
+    sys.memset(RGB_BUFFER, 0, FRAME_SIZE)
+    sys.memset(PREV_RGB_BUFFER, 0, FRAME_SIZE)
+
+    // Read the image packet (should be I-frame)
+    let packetType = seqread.readOneByte()
+
+    // Skip non-video packets until we find the image data
+    while (packetType !== TAV_PACKET_IFRAME) {
+        if (packetType === TAV_PACKET_EXTENDED_HDR) {
+            // Parse extended header - look for XFPS
+            let numPairs = seqread.readShort()
+            for (let i = 0; i < numPairs; i++) {
+                // Read key (4 bytes)
+                let keyBytes = seqread.readBytes(4)
+                let key = ""
+                for (let j = 0; j < 4; j++) {
+                    key += String.fromCharCode(sys.peek(keyBytes + j))
+                }
+                sys.free(keyBytes)
+
+                // Read value type and value
+                let valueType = seqread.readOneByte()
+                if (valueType === 0x04) {  // Uint64 - 8 bytes
+                    seqread.skip(8)
+                } else if (valueType === 0x10) {  // Bytes - length-prefixed
+                    let length = seqread.readShort()
+                    let dataBytes = seqread.readBytes(length)
+                    // Check for XFPS key
+                    if (key === "XFPS") {
+                        let xfpsStr = ""
+                        for (let j = 0; j < length; j++) {
+                            xfpsStr += String.fromCharCode(sys.peek(dataBytes + j))
+                        }
+                        parseXFPS(xfpsStr)
+                    }
+                    sys.free(dataBytes)
+                }
+            }
+        } else if (packetType === TAV_PACKET_SCREEN_MASK) {
+            // Skip screen mask packet - single entry: frame_num(4) + top(2) + right(2) + bottom(2) + left(2)
+            seqread.skip(12)
+        } else if (packetType === TAV_PACKET_TIMECODE) {
+            seqread.skip(8)
+        } else {
+            console.log(`got unknown packet type 0x${packetType.toString(16)}`)
+            let size = seqread.readInt()
+            seqread.skip(size)
+        }
+        packetType = seqread.readOneByte()
+    }
+
+    if (packetType === TAV_PACKET_IFRAME) {
+        // Read and decode I-frame
+        const compressedSize = seqread.readInt()
+        const compressedPtr = seqread.readBytes(compressedSize)
+
+        // Decode using TAV hardware decoder
+        graphics.tavDecodeCompressed(
+            compressedPtr, compressedSize,
+            RGB_BUFFER, PREV_RGB_BUFFER,
+            header.width, header.height,
+            header.qualityLevel,
+            QLUT[header.qualityY], QLUT[header.qualityCo], QLUT[header.qualityCg],
+            header.channelLayout, 0, header.waveletFilter, header.decompLevels,
+            isLossless, header.version, header.entropyCoder, 2
+        )
+        sys.free(compressedPtr)
+
+        // Upload to framebuffer
+        graphics.uploadRGBToFramebuffer(RGB_BUFFER, header.width, header.height, 0, false)
+
+    }
+
+    // Free buffers
+    sys.free(RGB_BUFFER)
+    sys.free(PREV_RGB_BUFFER)
+
+    // Show "backspace to exit" message
+    con.clear()
+    con.curs_set(0)
+    con.move(1, 1)
+    println("Push and hold Backspace to exit")
+
+    // Wait loop for still image viewing (similar to decodeipf.js)
+    let wait = true
+    let t1 = sys.nanoTime()
+    let tapNotifHideTimer = 0
+    const TAP_NOTIF_SHOWUPTIME = 3000000000  // 3 seconds
+
+    while (wait) {
+        sys.poke(-40, 1)
+        if (sys.peek(-41) == 67) {  // Backspace
+            wait = false
+            con.curs_set(1)
+        }
+
+        sys.sleep(50)
+
+        let t2 = sys.nanoTime()
+        tapNotifHideTimer += (t2 - t1)
+        if (tapNotifHideTimer > TAP_NOTIF_SHOWUPTIME) {
+            con.clear()
+        }
+        t1 = t2
+    }
+
+    // Clean up and exit (matching normal video playback cleanup)
+    con.clear()
+    con.curs_set(1)
+
+    // Reset font ROM
+    sys.poke(-1299460, 20)
+    sys.poke(-1299460, 21)
+
+    graphics.setPalette(0, 0, 0, 0, 0)
+    con.move(cy, cx) // restore cursor
+    return errorlevel
+}
+
 // Adjust decode height for interlaced content
 // For interlaced: header.height is display height (448)
 // Each field is half of display height (448/2 = 224)
@@ -998,10 +1150,10 @@ try {
                 else if (keyCode == 62) { // SPACE - pause/resume
                     paused = !paused
                     if (paused) {
-                        audio.stop(0)
+                        audio.stop(AUDIO_DEVICE)
                         serial.println(`Paused at frame ${frameCount}`)
                     } else {
-                        audio.play(0)
+                        audio.play(AUDIO_DEVICE)
                         serial.println(`Resumed`)
                     }
                 }
@@ -1022,10 +1174,10 @@ try {
                         baseTimecodeFrameCount = 0
                         currentTimecodeNs = 0
                         nextSubtitleEventIndex = 0  // Reset subtitle event processing
-                        audio.purgeQueue(0)
+                        audio.purgeQueue(AUDIO_DEVICE)
                         if (paused) {
-                            audio.play(0)
-                            audio.stop(0)
+                            audio.play(AUDIO_DEVICE)
+                            audio.stop(AUDIO_DEVICE)
                         }
                         skipped = true
                     }
@@ -1047,10 +1199,10 @@ try {
                         baseTimecodeFrameCount = 0
                         currentTimecodeNs = 0
                         nextSubtitleEventIndex = 0  // Reset subtitle event processing
-                        audio.purgeQueue(0)
+                        audio.purgeQueue(AUDIO_DEVICE)
                         if (paused) {
-                            audio.play(0)
-                            audio.stop(0)
+                            audio.play(AUDIO_DEVICE)
+                            audio.stop(AUDIO_DEVICE)
                         }
                         skipped = true
                     }
@@ -1078,10 +1230,10 @@ try {
                                 break
                             }
                         }
-                        audio.purgeQueue(0)
+                        audio.purgeQueue(AUDIO_DEVICE)
                         if (paused) {
-                            audio.play(0)
-                            audio.stop(0)
+                            audio.play(AUDIO_DEVICE)
+                            audio.stop(AUDIO_DEVICE)
                         }
                         skipped = true
                     }
@@ -1117,10 +1269,10 @@ try {
                                 break
                             }
                         }
-                        audio.purgeQueue(0)
+                        audio.purgeQueue(AUDIO_DEVICE)
                         if (paused) {
-                            audio.play(0)
-                            audio.stop(0)
+                            audio.play(AUDIO_DEVICE)
+                            audio.stop(AUDIO_DEVICE)
                         }
                         skipped = true
                     } else if (!seekTarget) {
@@ -1159,7 +1311,7 @@ try {
                     baseTimecodeFrameCount = 0
                     currentTimecodeNs = 0
                     nextSubtitleEventIndex = 0  // Reset subtitle event processing
-                    audio.purgeQueue(0)
+                    audio.purgeQueue(AUDIO_DEVICE)
                     currentFileIndex++
                     if (skipped) {
                         skipped = false
@@ -1170,7 +1322,7 @@ try {
 
                     console.log(`\nStarting file ${currentFileIndex}:`)
                     console.log(`Resolution: ${header.width}x${header.height}`)
-                    console.log(`FPS: ${header.fps}`)
+                    console.log(`FPS: ${header.fps === 255 ? "(see XFPS)" : header.fps}`)
                     console.log(`Total frames: ${header.totalFrames}`)
                     console.log(`Wavelet filter: ${header.waveletFilter === WAVELET_5_3_REVERSIBLE ? "5/3 reversible" : header.waveletFilter === WAVELET_9_7_IRREVERSIBLE ? "9/7 irreversible" : header.waveletFilter === WAVELET_BIORTHOGONAL_13_7 ? "Biorthogonal 13/7" : header.waveletFilter === WAVELET_DD4 ? "DD-4" : header.waveletFilter === WAVELET_HAAR ? "Haar" : "unknown"}`)
                     console.log(`Quality: Y=${header.qualityY}, Co=${header.qualityCo}, Cg=${header.qualityCg}`)
@@ -1583,7 +1735,7 @@ try {
 
                 seqread.readBytes(audioLen, SND_BASE_ADDR - 2368)
                 audio.mp2Decode()
-                audio.mp2UploadDecoded(0)
+                audio.mp2UploadDecoded(AUDIO_DEVICE)
 
             }
             else if (packetType === TAV_PACKET_AUDIO_TAD) {
@@ -1596,7 +1748,7 @@ try {
 
                 seqread.readBytes(payloadLen, SND_MEM_ADDR - 262144)
                 audio.tadDecode()
-                audio.tadUploadDecoded(0, sampleLen)
+                audio.tadUploadDecoded(AUDIO_DEVICE, sampleLen)
             }
             else if (packetType === TAV_PACKET_AUDIO_NATIVE) {
                 // PCM length must not exceed 65536 bytes!
@@ -1608,10 +1760,10 @@ try {
                 let pcmLen = gzip.decompFromTo(zstdPtr, zstdLen, pcmPtr) // <- segfaults!
                 if (pcmLen > 65536) throw Error(`PCM data too long -- got ${pcmLen} bytes`)
 
-                audio.putPcmDataByPtr(pcmPtr, pcmLen, 0)
+                audio.putPcmDataByPtr(AUDIO_DEVICE, pcmPtr, pcmLen, 0)
 
-                audio.setSampleUploadLength(0, pcmLen)
-                audio.startSampleUpload(0)
+                audio.setSampleUploadLength(AUDIO_DEVICE, pcmLen)
+                audio.startSampleUpload(AUDIO_DEVICE)
                 sys.free(zstdPtr)
 
                 sys.free(pcmPtr)
@@ -1704,7 +1856,19 @@ try {
                         }
                         sys.free(dataBytes)
 
-                        if (interactive) {
+                        // Parse XFPS if present (always try, not just when fps=255)
+                        if (key === "XFPS") {
+                            if (parseXFPS(dataStr)) {
+                                // Update frame timing with new fps
+                                frametime = 1000000000.0 / header.fps
+                                FRAME_TIME = 1.0 / header.fps
+                                if (interactive) {
+                                    serial.println(`  ${key}: ${dataStr} -> ${header.fps.toFixed(3)} fps`)
+                                }
+                            } else if (interactive) {
+                                serial.println(`  ${key}: "${dataStr}" (parse failed)`)
+                            }
+                        } else if (interactive) {
                             serial.println(`  ${key}: "${dataStr}"`)
                         }
                     } else {
@@ -1883,7 +2047,7 @@ try {
 
                 // Fire audio on first frame
                 if (!audioFired) {
-                    audio.play(0)
+                    audio.play(AUDIO_DEVICE)
                     audioFired = true
                 }
 
@@ -1971,7 +2135,7 @@ try {
 
                 // Fire audio on first frame
                 if (!audioFired) {
-                    audio.play(0)
+                    audio.play(AUDIO_DEVICE)
                     audioFired = true
                 }
 
@@ -2007,8 +2171,8 @@ try {
                     sys.memcpy(predecodedPcmBuffer + predecodedPcmOffset, SND_BASE_ADDR, uploadSize)
 
                     // Set upload parameters and trigger upload to queue
-                    audio.setSampleUploadLength(0, uploadSize)
-                    audio.startSampleUpload(0)
+                    audio.setSampleUploadLength(AUDIO_DEVICE, uploadSize)
+                    audio.startSampleUpload(AUDIO_DEVICE)
 
                     predecodedPcmOffset += uploadSize
                 }
@@ -2292,10 +2456,10 @@ finally {
     sys.poke(-1299460, 20)
     sys.poke(-1299460, 21)
 
-    audio.stop(0)
-    audio.purgeQueue(0)
+    audio.stop(AUDIO_DEVICE)
+    audio.purgeQueue(AUDIO_DEVICE)
 }
 
-graphics.setPalette(0, 0, 0, 0, 0)
+graphics.resetPalette()
 con.move(cy, cx) // restore cursor
 return errorlevel

assets/disk0/tvdos/bin/playwav.js

@@ -289,7 +289,7 @@ while (!stopPlay && seqread.getReadCount() < FILE_SIZE - 8) {
                     let decodedSampleLength = decodeInfilePcm(readPtr, decodePtr, readLength)
                     printdbg(`        decodedSampleLength: ${decodedSampleLength}`)
 
-                    audio.putPcmDataByPtr(decodePtr, decodedSampleLength, 0)
+                    audio.putPcmDataByPtr(0, decodePtr, decodedSampleLength, 0)
                     audio.setSampleUploadLength(0, decodedSampleLength)
                     audio.startSampleUpload(0)
 

assets/disk0/tvdos/bin/taut_fileop.js

@@ -0,0 +1,77 @@
+/**
+ * TAUT File Operations
+ * Sub-program launched by taut.js when the File tab is active.
+ * Rows 1-3 are owned by the parent; this program draws rows 4+.
+ *
+ * exec_args[1] = path to .taud file
+ * Sets _G.taut_nextPanel before returning to request a panel switch.
+ *
+ * Created by minjaesong on 2026-04-27
+ */
+
+const win = require("wintex")
+
+const PANEL_COUNT = 7
+const MY_PANEL   = 6 // VIEW_FILE
+
+const [SCRH, SCRW] = con.getmaxyx()
+const PANEL_Y = 4
+const PANEL_H = SCRH - PANEL_Y
+
+const colStatus  = 253
+const colContent = 240
+const colHdr     = 230
+
+function drawFileOpContents(wo) {
+    for (let y = PANEL_Y; y < SCRH; y++) {
+        con.move(y, 1)
+        con.color_pair(colContent, 255)
+        print(' '.repeat(SCRW))
+    }
+    con.move(PANEL_Y + 1, 3)
+    con.color_pair(colHdr, 255)
+    print('[ File ]')
+    con.move(PANEL_Y + 3, 3)
+    con.color_pair(colStatus, 255)
+    print('placeholder — not yet implemented')
+}
+
+function drawHints() {
+    con.move(SCRH, 1)
+    con.color_pair(colStatus, 255)
+    print(' '.repeat(SCRW - 1))
+    con.move(SCRH, 1)
+    con.color_pair(colHdr, 255); print('Tab ')
+    con.color_pair(colStatus, 255); print('Panel')
+}
+
+function fileOpInput(wo, event) {
+    // placeholder — no interaction yet
+}
+
+const panel = new win.WindowObject(1, PANEL_Y, SCRW, PANEL_H, fileOpInput, drawFileOpContents, undefined, ()=>{})
+
+panel.drawContents()
+drawHints()
+
+let done = false
+while (!done) {
+    input.withEvent(event => {
+        if (event[0] !== 'key_down') return
+        const keysym     = event[1]
+        const keyJustHit = (1 == event[2])
+        const shiftDown  = (event.includes(59) || event.includes(60))
+
+        if (!keyJustHit) return
+
+        if (keysym === '<TAB>') {
+            _G.taut_nextPanel = (MY_PANEL + (shiftDown ? -1 : 1) + PANEL_COUNT) % PANEL_COUNT
+            done = true
+            return
+        }
+
+        panel.processInput(event)
+    })
+}
+
+return 0

assets/disk0/tvdos/bin/taut_instredit.js

@@ -0,0 +1,77 @@
+/**
+ * TAUT Instrument Editor
+ * Sub-program launched by taut.js when the Instrmnt tab is active.
+ * Rows 1-3 are owned by the parent; this program draws rows 4+.
+ *
+ * exec_args[1] = path to .taud file
+ * Sets _G.taut_nextPanel before returning to request a panel switch.
+ *
+ * Created by minjaesong on 2026-04-27
+ */
+
+const win = require("wintex")
+
+const PANEL_COUNT = 7
+const MY_PANEL   = 4 // VIEW_INSTRMNT
+
+const [SCRH, SCRW] = con.getmaxyx()
+const PANEL_Y = 4
+const PANEL_H = SCRH - PANEL_Y
+
+const colStatus  = 253
+const colContent = 240
+const colHdr     = 230
+
+function drawInstEditContents(wo) {
+    for (let y = PANEL_Y; y < SCRH; y++) {
+        con.move(y, 1)
+        con.color_pair(colContent, 255)
+        print(' '.repeat(SCRW))
+    }
+    con.move(PANEL_Y + 1, 3)
+    con.color_pair(colHdr, 255)
+    print('[ Instrument Editor ]')
+    con.move(PANEL_Y + 3, 3)
+    con.color_pair(colStatus, 255)
+    print('placeholder — not yet implemented')
+}
+
+function drawHints() {
+    con.move(SCRH, 1)
+    con.color_pair(colStatus, 255)
+    print(' '.repeat(SCRW - 1))
+    con.move(SCRH, 1)
+    con.color_pair(colHdr, 255); print('Tab ')
+    con.color_pair(colStatus, 255); print('Panel')
+}
+
+function instEditInput(wo, event) {
+    // placeholder — no interaction yet
+}
+
+const panel = new win.WindowObject(1, PANEL_Y, SCRW, PANEL_H, instEditInput, drawInstEditContents, undefined, ()=>{})
+
+panel.drawContents()
+drawHints()
+
+let done = false
+while (!done) {
+    input.withEvent(event => {
+        if (event[0] !== 'key_down') return
+        const keysym     = event[1]
+        const keyJustHit = (1 == event[2])
+        const shiftDown  = (event.includes(59) || event.includes(60))
+
+        if (!keyJustHit) return
+
+        if (keysym === '<TAB>') {
+            _G.taut_nextPanel = (MY_PANEL + (shiftDown ? -1 : 1) + PANEL_COUNT) % PANEL_COUNT
+            done = true
+            return
+        }
+
+        panel.processInput(event)
+    })
+}
+
+return 0

assets/disk0/tvdos/bin/taut_sampleedit.js

@@ -0,0 +1,77 @@
+/**
+ * TAUT Sample Editor
+ * Sub-program launched by taut.js when the Samples tab is active.
+ * Rows 1-3 are owned by the parent; this program draws rows 4+.
+ *
+ * exec_args[1] = path to .taud file
+ * Sets _G.taut_nextPanel before returning to request a panel switch.
+ *
+ * Created by minjaesong on 2026-04-27
+ */
+
+const win = require("wintex")
+
+const PANEL_COUNT = 7
+const MY_PANEL   = 3 // VIEW_SAMPLES
+
+const [SCRH, SCRW] = con.getmaxyx()
+const PANEL_Y = 4
+const PANEL_H = SCRH - PANEL_Y
+
+const colStatus  = 253
+const colContent = 240
+const colHdr     = 230
+
+function drawSampleEditContents(wo) {
+    for (let y = PANEL_Y; y < SCRH; y++) {
+        con.move(y, 1)
+        con.color_pair(colContent, 255)
+        print(' '.repeat(SCRW))
+    }
+    con.move(PANEL_Y + 1, 3)
+    con.color_pair(colHdr, 255)
+    print('[ Sample Editor ]')
+    con.move(PANEL_Y + 3, 3)
+    con.color_pair(colStatus, 255)
+    print('placeholder — not yet implemented')
+}
+
+function drawHints() {
+    con.move(SCRH, 1)
+    con.color_pair(colStatus, 255)
+    print(' '.repeat(SCRW - 1))
+    con.move(SCRH, 1)
+    con.color_pair(colHdr, 255); print('Tab ')
+    con.color_pair(colStatus, 255); print('Panel')
+}
+
+function sampleEditInput(wo, event) {
+    // placeholder — no interaction yet
+}
+
+const panel = new win.WindowObject(1, PANEL_Y, SCRW, PANEL_H, sampleEditInput, drawSampleEditContents, undefined, ()=>{})
+
+panel.drawContents()
+drawHints()
+
+let done = false
+while (!done) {
+    input.withEvent(event => {
+        if (event[0] !== 'key_down') return
+        const keysym     = event[1]
+        const keyJustHit = (1 == event[2])
+        const shiftDown  = (event.includes(59) || event.includes(60))
+
+        if (!keyJustHit) return
+
+        if (keysym === '<TAB>') {
+            _G.taut_nextPanel = (MY_PANEL + (shiftDown ? -1 : 1) + PANEL_COUNT) % PANEL_COUNT
+            done = true
+            return
+        }
+
+        panel.processInput(event)
+    })
+}
+
+return 0

assets/disk0/tvdos/bin/tautbtn.r8

@@ -0,0 +1 @@
+<EFBFBD><EFBFBD>洄洄洄洄洄泚<EFBFBD>泚<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>_<EFBFBD>_

assets/disk0/tvdos/bin/tautbtn0.r8

@@ -0,0 +1 @@
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assets/disk0/tvdos/bin/zfm.js

@@ -1,4 +1,6 @@
 const win = require("wintex")
+const keys = require("keysym")
+
 const COL_TEXT = 253
 const COL_BACK = 255
 const COL_BACK_SEL = 81
@@ -26,37 +28,45 @@ const COL_HL_EXT = {
     "wav": 31,
     "adpcm": 31,
     "pcm": 32,
-    "mp3": 33,
+//    "mp3": 33,
     "tad": 33,
     "mp2": 34,
     "mv1": 213,
     "mv2": 213,
     "mv3": 213,
     "tav": 213,
+    "ipf": 190,
     "ipf1": 190,
     "ipf2": 190,
+    "im3": 190,
+    "tap": 190,
     "txt": 223,
     "md": 223,
-    "log": 223
+    "log": 223,
+    "taud":109,
 }
 
 const EXEC_FUNS = {
     "wav": (f) => _G.shell.execute(`playwav "${f}" -i`),
     "adpcm": (f) => _G.shell.execute(`playwav "${f}" -i`),
-    "mp3": (f) => _G.shell.execute(`playmp3 "${f}" -i`),
+//    "mp3": (f) => _G.shell.execute(`playmp3 "${f}" -i`),
     "mp2": (f) => _G.shell.execute(`playmp2 "${f}" -i`),
     "mv1": (f) => _G.shell.execute(`playmv1 "${f}" -i`),
     "mv2": (f) => _G.shell.execute(`playtev "${f}" -i`),
     "mv3": (f) => _G.shell.execute(`playtav "${f}" -i`),
     "tav": (f) => _G.shell.execute(`playtav "${f}" -i`),
+    "im3": (f) => _G.shell.execute(`playtav "${f}" -i`),
+    "tap": (f) => _G.shell.execute(`playtav "${f}" -i`),
     "tad": (f) => _G.shell.execute(`playtad "${f}" -i`),
     "pcm": (f) => _G.shell.execute(`playpcm "${f}" -i`),
+    "ipf": (f) => _G.shell.execute(`decodeipf "${f}" -i`),
     "ipf1": (f) => _G.shell.execute(`decodeipf "${f}" -i`),
     "ipf2": (f) => _G.shell.execute(`decodeipf "${f}" -i`),
     "bas": (f) => _G.shell.execute(`basic "${f}"`),
     "txt": (f) => _G.shell.execute(`less "${f}"`),
     "md": (f) => _G.shell.execute(`less "${f}"`),
-    "log": (f) => _G.shell.execute(`less "${f}"`)
+    "log": (f) => _G.shell.execute(`less "${f}"`),
+    "taud": (f) => _G.shell.execute(`taut "${f}"`),
 }
 
 let windowMode = 0 // 0 == left, 1 == right
@@ -665,7 +675,7 @@ while (!exit) {
         let keysym = event[1]
         let keyJustHit = (1 == event[2])
 
-        if (keyJustHit && event[3] != 66) { // release the latch right away if the key is not Return
+        if (keyJustHit && event[3] != keys.ENTER) { // release the latch right away if the key is not Return
             firstRunLatch = false
         }
 

assets/disk0/tvdos/include/font.mjs

@@ -0,0 +1,31 @@
+function setHighRom(fullPath) {
+    const fontFile = files.open(fullPath)
+
+    // upload font
+    const fontData = fontFile.bread()
+    for (let i = 0; i < 1920; i++) sys.poke(-133121 - i, fontData[i])
+    sys.poke(-1299460, 19) // write to high rom
+
+    fontFile.close()
+}
+
+function setLowRom(fullPath) {
+    const fontFile = files.open(fullPath)
+
+    // upload font
+    const fontData = fontFile.bread()
+    for (let i = 0; i < 1920; i++) sys.poke(-133121 - i, fontData[i])
+    sys.poke(-1299460, 18) // write to low rom
+
+    fontFile.close()
+}
+
+function resetHighRom() {
+    sys.poke(-1299460, 21)
+}
+
+function resetLowRom() {
+    sys.poke(-1299460, 20)
+}
+
+exports = { setHighRom, setLowRom, resetHighRom, resetLowRom }

assets/disk0/tvdos/include/getopt.mjs

@@ -0,0 +1,305 @@
+/*
+ * getopt.js: node.js implementation of POSIX getopt() (and then some)
+ *
+ * Copyright 2011 David Pacheco. All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+var ASSERT = require('assert').ok;
+
+function goError(msg)
+{
+	return (new Error('getopt: ' + msg));
+}
+
+/*
+ * The BasicParser is our primary interface to the outside world.  The
+ * documentation for this object and its public methods is contained in
+ * the included README.md.
+ */
+function goBasicParser(optstring, argv, optind)
+{
+	var ii;
+
+	ASSERT(optstring || optstring === '', 'optstring is required');
+	ASSERT(optstring.constructor === String, 'optstring must be a string');
+	ASSERT(argv, 'argv is required');
+	ASSERT(argv.constructor === Array, 'argv must be an array');
+
+	this.gop_argv = new Array(argv.length);
+	this.gop_options = {};
+	this.gop_aliases = {};
+	this.gop_optind = optind !== undefined ? optind : 2;
+	this.gop_subind = 0;
+
+	for (ii = 0; ii < argv.length; ii++) {
+		ASSERT(argv[ii].constructor === String,
+		    'argv must be string array');
+		this.gop_argv[ii] = argv[ii];
+	}
+
+	this.parseOptstr(optstring);
+}
+
+exports.BasicParser = goBasicParser;
+
+/*
+ * Parse the option string and update the following fields:
+ *
+ *	gop_silent	Whether to log errors to stderr.  Silent mode is
+ *			indicated by a leading ':' in the option string.
+ *
+ *	gop_options	Maps valid single-letter-options to booleans indicating
+ *			whether each option is required.
+ *
+ *	gop_aliases	Maps valid long options to the corresponding
+ *			single-letter short option.
+ */
+goBasicParser.prototype.parseOptstr = function (optstr)
+{
+	var chr, cp, alias, arg, ii;
+
+	ii = 0;
+	if (optstr.length > 0 && optstr[0] == ':') {
+		this.gop_silent = true;
+		ii++;
+	} else {
+		this.gop_silent = false;
+	}
+
+	while (ii < optstr.length) {
+		chr = optstr[ii];
+		arg = false;
+
+		if (!/^[\w\d\u1000-\u1100]$/.test(chr))
+			throw (goError('invalid optstring: only alphanumeric ' +
+			    'characters and unicode characters between ' +
+			    '\\u1000-\\u1100 may be used as options: ' + chr));
+
+		if (ii + 1 < optstr.length && optstr[ii + 1] == ':') {
+			arg = true;
+			ii++;
+		}
+
+		this.gop_options[chr] = arg;
+
+		while (ii + 1 < optstr.length && optstr[ii + 1] == '(') {
+			ii++;
+			cp = optstr.indexOf(')', ii + 1);
+			if (cp == -1)
+				throw (goError('invalid optstring: missing ' +
+				    '")" to match "(" at char ' + ii));
+
+			alias = optstr.substring(ii + 1, cp);
+			this.gop_aliases[alias] = chr;
+			ii = cp;
+		}
+
+		ii++;
+	}
+};
+
+goBasicParser.prototype.optind = function ()
+{
+	return (this.gop_optind);
+};
+
+/*
+ * For documentation on what getopt() does, see README.md.  The following
+ * implementation invariants are maintained by getopt() and its helper methods:
+ *
+ *	this.gop_optind		Refers to the element of gop_argv that contains
+ *				the next argument to be processed.  This may
+ *				exceed gop_argv, in which case the end of input
+ *				has been reached.
+ *
+ *	this.gop_subind		Refers to the character inside
+ *				this.gop_options[this.gop_optind] which begins
+ *				the next option to be processed.  This may never
+ *				exceed the length of gop_argv[gop_optind], so
+ *				when incrementing this value we must always
+ *				check if we should instead increment optind and
+ *				reset subind to 0.
+ *
+ * That is, when any of these functions is entered, the above indices' values
+ * are as described above.  getopt() itself and getoptArgument() may both be
+ * called at the end of the input, so they check whether optind exceeds
+ * argv.length.  getoptShort() and getoptLong() are called only when the indices
+ * already point to a valid short or long option, respectively.
+ *
+ * getopt() processes the next option as follows:
+ *
+ *	o If gop_optind > gop_argv.length, then we already parsed all arguments.
+ *
+ *	o If gop_subind == 0, then we're looking at the start of an argument:
+ *
+ *	    o Check for special cases like '-', '--', and non-option arguments.
+ *	      If present, update the indices and return the appropriate value.
+ *
+ *	    o Check for a long-form option (beginning with '--').  If present,
+ *	      delegate to getoptLong() and return the result.
+ *
+ *	    o Otherwise, advance subind past the argument's leading '-' and
+ *	      continue as though gop_subind != 0 (since that's now the case).
+ *
+ *	o Delegate to getoptShort() and return the result.
+ */
+goBasicParser.prototype.getopt = function ()
+{
+	if (this.gop_optind >= this.gop_argv.length)
+		/* end of input */
+		return (undefined);
+
+	var arg = this.gop_argv[this.gop_optind];
+
+	if (this.gop_subind === 0) {
+		if (arg == '-' || arg === '' || arg[0] != '-')
+			return (undefined);
+
+		if (arg == '--') {
+			this.gop_optind++;
+			this.gop_subind = 0;
+			return (undefined);
+		}
+
+		if (arg[1] == '-')
+			return (this.getoptLong());
+
+		this.gop_subind++;
+		ASSERT(this.gop_subind < arg.length);
+	}
+
+	return (this.getoptShort());
+};
+
+/*
+ * Implements getopt() for the case where optind/subind point to a short option.
+ */
+goBasicParser.prototype.getoptShort = function ()
+{
+	var arg, chr;
+
+	ASSERT(this.gop_optind < this.gop_argv.length);
+	arg = this.gop_argv[this.gop_optind];
+	ASSERT(this.gop_subind < arg.length);
+	chr = arg[this.gop_subind];
+
+	if (++this.gop_subind >= arg.length) {
+		this.gop_optind++;
+		this.gop_subind = 0;
+	}
+
+	if (!(chr in this.gop_options))
+		return (this.errInvalidOption(chr));
+
+	if (!this.gop_options[chr])
+		return ({ option: chr });
+
+	return (this.getoptArgument(chr));
+};
+
+/*
+ * Implements getopt() for the case where optind/subind point to a long option.
+ */
+goBasicParser.prototype.getoptLong = function ()
+{
+	var arg, alias, chr, eq;
+
+	ASSERT(this.gop_subind === 0);
+	ASSERT(this.gop_optind < this.gop_argv.length);
+	arg = this.gop_argv[this.gop_optind];
+	ASSERT(arg.length > 2 && arg[0] == '-' && arg[1] == '-');
+
+	eq = arg.indexOf('=');
+	alias = arg.substring(2, eq == -1 ? arg.length : eq);
+	if (!(alias in this.gop_aliases))
+		return (this.errInvalidOption(alias));
+
+	chr = this.gop_aliases[alias];
+	ASSERT(chr in this.gop_options);
+
+	if (!this.gop_options[chr]) {
+		if (eq != -1)
+			return (this.errExtraArg(alias));
+
+		this.gop_optind++; /* eat this argument */
+		return ({ option: chr });
+	}
+
+	/*
+	 * Advance optind/subind for the argument value and retrieve it.
+	 */
+	if (eq == -1)
+		this.gop_optind++;
+	else
+		this.gop_subind = eq + 1;
+
+	return (this.getoptArgument(chr));
+};
+
+/*
+ * For the given option letter 'chr' that takes an argument, assumes that
+ * optind/subind point to the argument (or denote the end of input) and return
+ * the appropriate getopt() return value for this option and argument (or return
+ * the appropriate error).
+ */
+goBasicParser.prototype.getoptArgument = function (chr)
+{
+	var arg;
+
+	if (this.gop_optind >= this.gop_argv.length)
+		return (this.errMissingArg(chr));
+
+	arg = this.gop_argv[this.gop_optind].substring(this.gop_subind);
+	this.gop_optind++;
+	this.gop_subind = 0;
+	return ({ option: chr, optarg: arg });
+};
+
+goBasicParser.prototype.errMissingArg = function (chr)
+{
+	if (this.gop_silent)
+		return ({ option: ':', optopt: chr });
+
+	process.stderr.write('option requires an argument -- ' + chr + '\n');
+	return ({ option: '?', optopt: chr, error: true });
+};
+
+goBasicParser.prototype.errInvalidOption = function (chr)
+{
+	if (!this.gop_silent)
+		process.stderr.write('illegal option -- ' + chr + '\n');
+
+	return ({ option: '?', optopt: chr, error: true });
+};
+
+/*
+ * This error is not specified by POSIX, but neither is the notion of specifying
+ * long option arguments using "=" in the same argv-argument, but it's common
+ * practice and pretty convenient.
+ */
+goBasicParser.prototype.errExtraArg = function (chr)
+{
+	if (!this.gop_silent)
+		process.stderr.write('option expects no argument -- ' +
+		    chr + '\n');
+
+	return ({ option: '?', optopt: chr, error: true });
+};

assets/disk0/tvdos/include/gl.mjs

@@ -1,7 +1,7 @@
-/*
-TVDOS Graphics Library
-
-Has no affiliation with OpenGL by Khronos Group
+/**
+ * LibGL — TVDOS Graphics Library
+ * Has no affiliation with OpenGL by Khronos Group
+ * @author CuriousTorvald
  */
 
 
@@ -45,7 +45,7 @@ exports.SpriteSheet = function(tilew, tileh, tex) {
         return ty;
     };
 };
-exports.drawTexPattern = function(texture, x, y, width, height, framebuffer, fgcol, bgcol) {
+exports.drawTexPattern = function(texture, x, y, width = texture.width, height = texture.height, framebuffer = false, fgcol, bgcol) {
     if (!(texture instanceof exports.Texture) && !(texture instanceof exports.MonoTex)) throw Error("Texture is not a GL Texture types");
 
     let paint = (!framebuffer) ? graphics.plotPixel : graphics.plotPixel2

assets/disk0/tvdos/include/keysym.mjs

@@ -0,0 +1,80 @@
+/**
+ * These are key symbols returned by `input.withEvent`, NOT `con.getch()`
+ */
+
+exports = {
+NUM_0:7,
+NUM_1:8,
+NUM_2:9,
+NUM_3:10,
+NUM_4:11,
+NUM_5:12,
+NUM_6:13,
+NUM_7:14,
+NUM_8:15,
+NUM_9:16,
+A:29,
+ALT_LEFT:57,
+ALT_RIGHT:58,
+APOSTROPHE:75,
+AT:77,
+B:30,
+BACK:4,
+BACKSLASH:73,
+C:31,
+CAPS_LOCK:115,
+COMMA:55,
+D:32,
+DEL:67,
+BACKSPACE:67,
+FORWARD_DEL:112,
+DOWN:20,
+LEFT:21,
+RIGHT:22,
+UP:19,
+E:33,
+ENTER:66,
+EQUALS:70,
+F:34,
+G:35,
+GRAVE:68,
+H:36,
+HOME:3,
+I:37,
+J:38,
+K:39,
+L:40,
+LEFT_BRACKET:71,
+M:41,
+MINUS:69,
+N:42,
+O:43,
+P:44,
+PERIOD:56,
+PLUS:81,
+Q:45,
+R:46,
+RIGHT_BRACKET:72,
+S:47,
+SEMICOLON:74,
+SHIFT_LEFT:59,
+SHIFT_RIGHT:60,
+SLASH:76,
+SPACE:62,
+SYM:63, // on MacOS, this is Command (⌘)
+T:48,
+TAB:61,
+U:49,
+V:50,
+W:51,
+X:52,
+Y:53,
+Z:54,
+CONTROL_LEFT:129,
+CONTROL_RIGHT:130,
+ESCAPE:111,
+END:123,
+INSERT:124,
+PAGE_UP:92,
+PAGE_DOWN:93,
+}

assets/disk0/tvdos/include/pcm.mjs

@@ -1,3 +1,8 @@
+/**
+ * LibPCM — PCM decoder for TSVM
+ * @author CuriousTorvald
+ */
+
 const HW_SAMPLING_RATE = 32000
 function printdbg(s) { if (0) serial.println(s) }
 function printvis(s) { if (0) println(s) }
@@ -29,7 +34,7 @@ function s16Tou8(i) {
 }
 function u16Tos16(i) { return (i > 32767) ? i - 65536 : i }
 function randomRound(k) {
-    let rnd = (Math.random() + Math.random()) / 2.0 // this produces triangular distribution
+    let rnd = Math.random() // note to self: no triangular here
     return (rnd < (k - (k|0))) ? Math.ceil(k) : Math.floor(k)
 }
 function lerp(start, end, x) {

assets/disk0/tvdos/include/psg.mjs

@@ -0,0 +1,414 @@
+/**
+ * LibPSG — PSG emulator and mixer for TSVM
+ * Software-mixes various PSG channels and sends them to sound device as PCM
+ * @author CuriousTorvald
+ */
+
+const HW_SAMPLING_RATE = 32000
+
+function clamp(val, low, hi) { return (val < low) ? low : (val > hi) ? hi : val }
+function clampS16(i) { return clamp(i, -32768, 32767) }
+const uNybToSnyb = [0,1,2,3,4,5,6,7,-8,-7,-6,-5,-4,-3,-2,-1]
+// returns: [unsigned high, unsigned low, signed high, signed low]
+function getNybbles(b) { return [b >> 4, b & 15, uNybToSnyb[b >> 4], uNybToSnyb[b & 15]] }
+function s8Tou8(i) { return i + 128 }
+function s16Tou8(i) {
+//    return s8Tou8((i >> 8) & 255)
+    // apply dithering
+    let ufval = (i / 65536.0) + 0.5
+    let ival = randomRound(ufval * 255.0)
+    return ival|0
+}
+function u16Tos16(i) { return (i > 32767) ? i - 65536 : i }
+function randomRound(k) {
+    let rnd = Math.random() // note to self: no triangular here
+    return (rnd < (k - (k|0))) ? Math.ceil(k) : Math.floor(k)
+}
+function lerp(start, end, x) {
+    return (1 - x) * start + x * end
+}
+function lerpAndRound(start, end, x) {
+    return Math.round(lerp(start, end, x))
+}
+
+
+
+// output format: immediately uploadable into TSVM audio adapter
+
+// ── Internal helpers ────────────────────────────────────────────────────────
+
+function secToSamples(sec) { return Math.round(HW_SAMPLING_RATE * sec) }
+
+function isNative(buf) { return buf.native }
+
+function readU8(buf, ch, i) {
+    return isNative(buf) ? (sys.peek(buf[ch] + i) & 255) : buf[ch][i]
+}
+function writeU8(buf, ch, i, v) {
+    if (isNative(buf)) sys.poke(buf[ch] + i, v)
+    else buf[ch][i] = v
+}
+
+// ── Buffer management ───────────────────────────────────────────────────────
+
+function makeBuffer(length) {
+    // returns [Uint8Array, Uint8Array] (stereo) that will be used to collect samples made by LibPSG.
+    // Length: seconds. Number of elements: round(HW_SAMPLING_RATE * length)
+    const n = secToSamples(length)
+    const L = new Uint8Array(n)
+    const R = new Uint8Array(n)
+    L.fill(128)
+    R.fill(128)
+    return { 0: L, 1: R, samples: n, native: false }
+}
+
+function makeBufferNative(length) {
+    // returns native buffer object (stereo) that will be used to collect samples made by LibPSG.
+    // Length: seconds. Number of elements: round(HW_SAMPLING_RATE * length)
+    // Free with freeBufferNative() when done.
+    const n = secToSamples(length)
+    const L = sys.malloc(n); sys.memset(L, 128, n)
+    const R = sys.malloc(n); sys.memset(R, 128, n)
+    return { 0: L, 1: R, samples: n, native: true }
+}
+
+function freeBufferNative(buf) {
+    sys.free(buf[0])
+    sys.free(buf[1])
+}
+
+function clearBuffer(buf, offsetSec, lengthSec) {
+    // Re-silence a buffer region (fill with 128) for re-use across frames.
+    const start = (offsetSec != null) ? secToSamples(offsetSec) : 0
+    const total = (lengthSec != null) ? secToSamples(lengthSec) : (buf.samples - start)
+    if (!buf.native) {
+        buf[0].fill(128, start, start + total)
+        buf[1].fill(128, start, start + total)
+    } else {
+        sys.memset(buf[0] + start, 128, total)
+        sys.memset(buf[1] + start, 128, total)
+    }
+}
+
+// ── Shared mix core ─────────────────────────────────────────────────────────
+
+// sampleFn(i) must return a float in [-1, 1].
+// Mixing maths: decode u8 → s16, apply op, clamp, dither back to u8.
+function mixInto(buf, lengthSec, offsetSec, op, amp, pan, sampleFn) {
+    const startIdx = secToSamples(offsetSec)
+    const n = secToSamples(lengthSec)
+    // Linear pan law: centre (pan=0) → both channels at full amp
+    const gainL = Math.max(0, Math.min(1, 1.0 - pan))
+    const gainR = Math.max(0, Math.min(1, 1.0 + pan))
+    const opCode = (op === 'sub') ? 1 : (op === 'mul') ? 2 : 0  // default: add
+    for (let i = 0; i < n; i++) {
+        const v = sampleFn(i)           // oscillator value in [-1, 1]
+        const oscBase = v * amp * 32767
+        const oscL = Math.round(oscBase * gainL) | 0
+        const oscR = Math.round(oscBase * gainR) | 0
+        for (let ch = 0; ch < 2; ch++) {
+            const osc = (ch === 0) ? oscL : oscR
+            const cur = (readU8(buf, ch, startIdx + i) - 128) << 8
+            let out
+            switch (opCode) {
+                case 0: out = cur + osc; break
+                case 1: out = cur - osc; break
+                case 2: out = (cur * osc) >> 15; break
+            }
+            writeU8(buf, ch, startIdx + i, s16Tou8(clampS16(out)))
+        }
+    }
+}
+
+// ── Waveform generators ─────────────────────────────────────────────────────
+
+function makeSquare(buf, length, offset, freq, duty, op, amp, pan, phaseOffset) {
+    // buffer: [Uint8Array, Uint8Array] or native buffer
+    // length: in seconds
+    // offset: in seconds
+    // duty: 0.0 to 1.0. default 0.5 (fraction of period where output is +1)
+    // freq: Hz
+    // op: add / mul / sub; default: add
+    // amp: 0.0 to 1.0; default: 0.5
+    // pan: -1.0 to 1.0; default: 0.0
+    // phaseOffset: optional absolute-time base (seconds) added to phase calc only,
+    //              not to the buffer write position — use to ensure phase continuity
+    //              across successive calls (e.g. frame boundaries).
+    if (duty == null) duty = 0.5
+    if (op   == null) op   = 'add'
+    if (amp  == null) amp  = 0.5
+    if (pan  == null) pan  = 0.0
+    const tBase = (phaseOffset || 0) + offset
+    mixInto(buf, length, offset, op, amp, pan, function(i) {
+        const phase = ((tBase + i / HW_SAMPLING_RATE) * freq) % 1
+        return (phase < duty) ? 1.0 : -1.0
+    })
+}
+
+function makeTriangle(buf, length, offset, freq, duty, op, amp, pan, phaseOffset) {
+    // buffer: [Uint8Array, Uint8Array] or native buffer
+    // length: in seconds
+    // offset: in seconds
+    // duty: skew. -1.0 = falling sawtooth, 0.0 = symmetric triangle, 1.0 = rising sawtooth
+    // freq: Hz
+    // op: add / mul / sub; default: add
+    // amp: 0.0 to 1.0; default: 0.5
+    // pan: -1.0 to 1.0; default: 0.0
+    // phaseOffset: optional absolute-time base (seconds) added to phase calc only —
+    //              see makeSquare for details.
+    if (duty == null) duty = 0.0
+    if (op   == null) op   = 'add'
+    if (amp  == null) amp  = 0.5
+    if (pan  == null) pan  = 0.0
+    // riseFrac: fraction of period spent rising from -1 to +1
+    // 0.0 → falling saw, 0.5 → symmetric triangle, 1.0 → rising saw
+    const riseFrac = (duty + 1.0) * 0.5
+    const tBase = (phaseOffset || 0) + offset
+    mixInto(buf, length, offset, op, amp, pan, function(i) {
+        const phase = ((tBase + i / HW_SAMPLING_RATE) * freq) % 1
+        if (riseFrac <= 0) {
+            return 1.0 - 2.0 * phase                               // falling saw
+        } else if (riseFrac >= 1) {
+            return -1.0 + 2.0 * phase                              // rising saw
+        } else if (phase < riseFrac) {
+            return -1.0 + 2.0 * (phase / riseFrac)                 // rising slope
+        } else {
+            return 1.0 - 2.0 * ((phase - riseFrac) / (1.0 - riseFrac)) // falling slope
+        }
+    })
+}
+
+function makeAliasedTriangle(buf, length, offset, freq, duty, op, amp, pan, phaseOffset) {
+    // buffer: [Uint8Array, Uint8Array] or native buffer
+    // Famicom-style triangle — output is quantised to 16 DAC levels (4-bit, NES APU style).
+    // The staircase quantisation introduces harmonics that mimic NES character.
+    // length: in seconds
+    // offset: in seconds
+    // duty: skew. -1.0 = falling sawtooth, 0.0 = symmetric triangle, 1.0 = rising sawtooth
+    // freq: Hz
+    // op: add / mul / sub; default: add
+    // amp: 0.0 to 1.0; default: 0.5
+    // pan: -1.0 to 1.0; default: 0.0
+    // phaseOffset: optional absolute-time base (seconds) added to phase calc only —
+    //              see makeSquare for details.
+    if (duty == null) duty = 0.0
+    if (op   == null) op   = 'add'
+    if (amp  == null) amp  = 0.5
+    if (pan  == null) pan  = 0.0
+    const riseFrac = (duty + 1.0) * 0.5
+    const tBase = (phaseOffset || 0) + offset
+    mixInto(buf, length, offset, op, amp, pan, function(i) {
+        const phase = ((tBase + i / HW_SAMPLING_RATE) * freq) % 1
+        let v
+        if (riseFrac <= 0) {
+            v = 1.0 - 2.0 * phase
+        } else if (riseFrac >= 1) {
+            v = -1.0 + 2.0 * phase
+        } else if (phase < riseFrac) {
+            v = -1.0 + 2.0 * (phase / riseFrac)
+        } else {
+            v = 1.0 - 2.0 * ((phase - riseFrac) / (1.0 - riseFrac))
+        }
+        // Quantise to 16 levels (NES triangle 4-bit DAC: 0..15 → -1..+1)
+        const level = Math.max(0, Math.min(15, Math.round((v + 1.0) * 7.5)))
+        return level / 7.5 - 1.0
+    })
+}
+
+// ── LFSR helpers (for noise types 1 and 2) ─────────────────────────────────
+
+function lfsrStep(state, mode) {
+    // mode 0 (long/NES mode 0): feedback tap at bit 1; period 32767
+    // mode 1 (short/NES mode 1): feedback tap at bit 6; period 93 (metallic/tonal)
+    const bit0   = state & 1
+    const bitTap = (mode === 0) ? (state >> 1) & 1 : (state >> 6) & 1
+    const feed   = bit0 ^ bitTap
+    return ((feed << 14) | (state >> 1)) & 0x7FFF
+}
+
+function lfsrAdvance(state, steps, mode) {
+    for (let k = 0; k < steps; k++) state = lfsrStep(state, mode)
+    return state
+}
+
+// NES APU documented LFSR periods
+const LFSR_PERIOD_LONG  = 32767  // mode 0
+const LFSR_PERIOD_SHORT = 93     // mode 1
+
+function makeNoise(buf, length, offset, freq, type, op, amp, pan, phaseOffset) {
+    // buffer: [Uint8Array, Uint8Array] or native buffer
+    // length: in seconds
+    // offset: in seconds
+    // type:
+    //   -1: 8-bit white noise (random float per period, sample-and-hold)
+    //    0: 1-bit white noise (random ±1 per period, sample-and-hold)
+    //    1: 1-bit LFSR long mode  — NES mode 0, tap=bit0^bit1, period 32767 (full-spectrum)
+    //    2: 1-bit LFSR short mode — NES mode 1, tap=bit0^bit6, period 93 (metallic/tonal)
+    // freq: Hz (clock rate of the noise generator)
+    // op: add / mul / sub; default: add
+    // amp: 0.0 to 1.0; default: 0.5
+    // pan: -1.0 to 1.0; default: 0.0
+    // phaseOffset: optional absolute-time base (seconds) added to phase/LFSR calc only —
+    //              see makeSquare for details.
+    //
+    // LFSR types (1 and 2) are deterministic given (phaseOffset+offset, freq): calling
+    // with monotonically advancing phaseOffset+offset produces a seamless noise stream
+    // across frames. White noise types (-1, 0) are random per call.
+    if (op  == null) op  = 'add'
+    if (amp == null) amp = 0.5
+    if (pan == null) pan = 0.0
+    const tBase = (phaseOffset || 0) + offset
+
+    if (type === -1) {
+        // 8-bit white: new random float in [-1, 1] each clock period
+        let prevClock = -1
+        let noiseVal = 0.0
+        mixInto(buf, length, offset, op, amp, pan, function(i) {
+            const currentClock = Math.floor((tBase + i / HW_SAMPLING_RATE) * freq) | 0
+            if (currentClock !== prevClock) {
+                prevClock = currentClock
+                noiseVal = Math.random() * 2.0 - 1.0
+            }
+            return noiseVal
+        })
+    } else if (type === 0) {
+        // 1-bit white: random ±1 each clock period
+        let prevClock = -1
+        let noiseVal = 1.0
+        mixInto(buf, length, offset, op, amp, pan, function(i) {
+            const currentClock = Math.floor((tBase + i / HW_SAMPLING_RATE) * freq) | 0
+            if (currentClock !== prevClock) {
+                prevClock = currentClock
+                noiseVal = (Math.random() >= 0.5) ? 1.0 : -1.0
+            }
+            return noiseVal
+        })
+    } else {
+        // LFSR-based noise (types 1 and 2)
+        const mode   = (type === 2) ? 1 : 0
+        const period = (mode === 0) ? LFSR_PERIOD_LONG : LFSR_PERIOD_SHORT
+        // Advance to deterministic position for this tBase so consecutive frame
+        // calls with monotonically advancing phaseOffset produce a seamless noise stream.
+        const startClock = Math.floor(tBase * freq) | 0
+        let lfsr      = lfsrAdvance(1, startClock % period, mode)
+        let prevClock = startClock
+        mixInto(buf, length, offset, op, amp, pan, function(i) {
+            const currentClock = Math.floor((tBase + i / HW_SAMPLING_RATE) * freq) | 0
+            const delta = currentClock - prevClock
+            if (delta > 0) {
+                const steps = delta % period
+                if (steps > 0) lfsr = lfsrAdvance(lfsr, steps, mode)
+                prevClock = currentClock
+            }
+            return (lfsr & 1) ? 1.0 : -1.0
+        })
+    }
+}
+
+function makeAliasedTriangleNES(buf, length, offset, freq, duty, op, amp, pan, phaseOffset) {
+    // NES APU triangle — quantised to the authentic 32-step, 4-bit (0..15) staircase.
+    // The 32-step sequence is: 15,14,...,1,0, 0,1,...,14,15 (descending then ascending).
+    // This mirrors the real NES triangle DAC which has 32 equal-height steps per period.
+    // duty parameter is accepted for API symmetry but ignored (NES triangle is always symmetric).
+    // phaseOffset: optional absolute-time base (seconds) — see makeSquare for details.
+    if (op  == null) op  = 'add'
+    if (amp == null) amp = 0.5
+    if (pan == null) pan = 0.0
+    const tBase = (phaseOffset || 0) + offset
+    mixInto(buf, length, offset, op, amp, pan, function(i) {
+        const phase = ((tBase + i / HW_SAMPLING_RATE) * freq) % 1
+        const step32 = Math.floor(phase * 32) | 0  // 0..31
+        // step 0..15: descend from 15 to 0; step 16..31: ascend from 0 to 15
+        const level = (step32 < 16) ? (15 - step32) : (step32 - 16)
+        return level / 7.5 - 1.0  // map 0..15 → -1..+1
+    })
+}
+
+// ── Send to audio hardware ──────────────────────────────────────────────────
+
+function sendBuffer(buf, playhead, offsetSec, lengthSec, stagingPtr) {
+    // Interleaves the L and R channels into a staging region (LRLRLR…) and uploads
+    // to the audio adapter pcmBin via the standard putPcmDataByPtr pipeline.
+    //
+    // offsetSec:  start of region to send (default: 0)
+    // lengthSec:  duration to send (default: entire buffer from offsetSec)
+    // stagingPtr: optional caller-owned native buffer (≥ min(chunk, 32768) * 2 bytes).
+    //             Pass a pre-allocated pointer to avoid malloc/free per call —
+    //             useful for the per-frame tvnes pattern.
+    //
+    // The function auto-chunks at 32768 stereo samples (pcmBin capacity).
+    // Blocks briefly if the audio queue is saturated (queue depth > 2).
+    const start = (offsetSec != null) ? secToSamples(offsetSec) : 0
+    const total = (lengthSec != null) ? secToSamples(lengthSec) : (buf.samples - start)
+    const MAX_CHUNK = 32768  // pcmBin = 65536 bytes; stereo → max 32768 samples per upload
+    const ownsStaging = (stagingPtr == null)
+    if (ownsStaging) stagingPtr = sys.malloc(Math.min(total, MAX_CHUNK) * 2)
+
+    let remaining = total
+    let cursor    = start
+    while (remaining > 0) {
+        const take = Math.min(remaining, MAX_CHUNK)
+        // Interleave L, R into staging buffer
+        for (let i = 0; i < take; i++) {
+            sys.poke(stagingPtr + 2 * i,     readU8(buf, 0, cursor + i))
+            sys.poke(stagingPtr + 2 * i + 1, readU8(buf, 1, cursor + i))
+        }
+        // Wait for room in the playback queue (mirrors playwav.js idiom)
+        // while (audio.getPosition(playhead) > 2) sys.sleep(2)
+        audio.putPcmDataByPtr(playhead, stagingPtr, take * 2, 0)
+        audio.setSampleUploadLength(playhead, take * 2)
+        audio.startSampleUpload(playhead)
+        remaining -= take
+        cursor    += take
+    }
+
+    if (ownsStaging) sys.free(stagingPtr)
+}
+
+// Lazily-allocated JS-side interleave scratch; shared across sendBufferFast calls.
+let _sendFastScratch = null
+
+function sendBufferFast(buf, playhead, offsetSec, lengthSec, stagingPtr) {
+    // Like sendBuffer but interleaves L/R via a JS Uint8Array + one sys.pokeBytes per chunk,
+    // instead of ~2n sys.poke calls.  Requires a non-native (JS-backed) buffer.
+    // Falls back to sendBuffer for native buffers.
+    if (isNative(buf)) { sendBuffer(buf, playhead, offsetSec, lengthSec, stagingPtr); return }
+
+    const start = (offsetSec != null) ? secToSamples(offsetSec) : 0
+    const total = (lengthSec != null) ? secToSamples(lengthSec) : (buf.samples - start)
+    const MAX_CHUNK = 32768
+    const ownsStaging = (stagingPtr == null)
+    if (ownsStaging) stagingPtr = sys.malloc(Math.min(total, MAX_CHUNK) * 2)
+
+    const scratchNeeded = Math.min(total, MAX_CHUNK) * 2
+    if (_sendFastScratch == null || _sendFastScratch.length < scratchNeeded) {
+        _sendFastScratch = new Uint8Array(scratchNeeded)
+    }
+
+    let remaining = total
+    let cursor    = start
+    while (remaining > 0) {
+        const take = Math.min(remaining, MAX_CHUNK)
+        const L = buf[0], R = buf[1], sc = _sendFastScratch
+        for (let i = 0; i < take; i++) {
+            sc[2 * i]     = L[cursor + i]
+            sc[2 * i + 1] = R[cursor + i]
+        }
+        sys.pokeBytes(stagingPtr, sc.subarray(0, take * 2), take * 2)
+        // while (audio.getPosition(playhead) > 2) sys.sleep(2)
+        audio.putPcmDataByPtr(playhead, stagingPtr, take * 2, 0)
+        audio.setSampleUploadLength(playhead, take * 2)
+        audio.startSampleUpload(playhead)
+        remaining -= take
+        cursor    += take
+    }
+
+    if (ownsStaging) sys.free(stagingPtr)
+}
+
+exports = {
+    HW_SAMPLING_RATE,
+    makeBuffer, makeBufferNative, freeBufferNative, clearBuffer,
+    makeSquare, makeTriangle, makeAliasedTriangle, makeAliasedTriangleNES, makeNoise,
+    sendBuffer, sendBufferFast
+}

assets/disk0/tvdos/include/seqread.mjs

@@ -1,4 +1,7 @@
-
+/**
+ * LibSeqread — sequentially read files from disk drive
+ * @author CuriousTorvald
+ */
 let readCount = 0
 let port = undefined
 let fileHeader = new Uint8Array(4096)

assets/disk0/tvdos/include/seqreadtape.mjs

@@ -1,3 +1,8 @@
+/**
+ * LibSeqread extension for Tape Drive — sequentially read tape
+ * @author CuriousTorvald
+ */
+
 // Sequential reader for HSDPA TAPE devices
 // Unlike seqread.mjs which is limited to 4096 bytes per read due to serial communication,
 // this module can read larger chunks efficiently from HSDPA devices.

assets/disk0/tvdos/include/taud.mjs

@@ -0,0 +1,312 @@
+/*
+ * LibTaud — Helper functions for interaction between Taud format and TSVM Tracker
+ * Requires TVDOS to function.
+ * @author CuriousTorvald
+ */
+
+// ── Format constants ────────────────────────────────────────────────────────
+
+const TAUD_MAGIC        = [0x1F,0x54,0x53,0x56,0x4D,0x61,0x75,0x64]  // \x1F TSVMaud
+const TAUD_VERSION      = 1
+const TAUD_HEADER_SIZE  = 32     // magic(8) + version(1) + numSongs(1) + compSize(4) + projOff(4) + sig(14)
+const TAUD_SONG_ENTRY   = 32     // see encodeSongEntry / decodeSongEntry below
+const SAMPLEINST_SIZE   = 786432 // 737280 sample + 49152 instrument (256 × 192)
+const PATTERN_SIZE      = 512    // bytes per pattern (64 rows × 8 bytes)
+const NUM_PATTERNS_MAX  = 256
+const NUM_CUES          = 1024
+const CUE_SIZE          = 32     // bytes per cue entry (packed 12-bit×20 voices + instruction + pad)
+
+// Signature written into the file (14 bytes, space-padded)
+const CAPTURE_SIGNATURE = "LibTaud/TSVM  "
+
+// ── Internal helpers ────────────────────────────────────────────────────────
+
+function _peekU32LE(ptr, off) {
+    return ((sys.peek(ptr+off)   & 0xFF)       ) |
+           ((sys.peek(ptr+off+1) & 0xFF) <<  8 ) |
+           ((sys.peek(ptr+off+2) & 0xFF) << 16 ) |
+           ((sys.peek(ptr+off+3) & 0xFF) * 0x1000000)  // avoid sign-extend
+}
+
+function _pokeU32LE(ptr, off, v) {
+    sys.poke(ptr+off,   (v        ) & 0xFF)
+    sys.poke(ptr+off+1, (v >>>  8) & 0xFF)
+    sys.poke(ptr+off+2, (v >>> 16) & 0xFF)
+    sys.poke(ptr+off+3, (v >>> 24) & 0xFF)
+}
+
+// ── uploadTaudFile ──────────────────────────────────────────────────────────
+
+/**
+ * Load one song from a Taud file into the tracker hardware and configure the
+ * given playhead ready to play.
+ *
+ * @param inFile             Full path with drive letter, e.g. "A:/music/song.taud"
+ * @param songIndex          0-based index of the song in the SONG TABLE
+ * @param playhead Playhead number (0-3) to configure
+ */
+function uploadTaudFile(inFile, songIndex, playhead) {
+    const drive    = inFile[0].toUpperCase()
+    const diskPath = inFile.substring(2)
+
+    const memBase  = audio.getMemAddr()
+
+    // -- 1. Read whole file into VM memory ------------------------------------
+    const fileHandle = files.open(inFile)
+
+    if (!fileHandle.exists) {
+        throw Error("taud: file not exists")
+    }
+
+    const fileSize = fileHandle.size
+    const filePtr  = sys.malloc(fileSize)
+    fileHandle.pread(filePtr, fileSize, 0)
+
+    let pos = 0
+
+    // -- 2. Verify magic ------------------------------------------------------
+    for (let i = 0; i < 8; i++) {
+        let magicc = sys.peek(filePtr + i)
+        if (magicc !== TAUD_MAGIC[i]) {
+            sys.free(filePtr)
+            throw Error("taud: bad magic byte " + magicc.toString(16) + " at index " + i)
+        }
+    }
+    pos = 8
+
+    // -- 3. Parse header ------------------------------------------------------
+    // version(1) + numSongs(1) + compressedSize(4) + rsvd(2) + signature(16) = 24 bytes
+    let version        = sys.peek(filePtr + pos) & 0xFF;  pos++
+    let numSongs       = sys.peek(filePtr + pos) & 0xFF;  pos++
+    let compressedSize = _peekU32LE(filePtr, pos);         pos += 4
+    pos += 18  // skip reserved(2) + signature(16)
+    // pos == 32 == TAUD_HEADER_SIZE
+
+    if (songIndex < 0 || songIndex >= numSongs) {
+        sys.free(filePtr)
+        throw Error("taud: songIndex " + songIndex + " out of range (numSongs=" + numSongs + ")")
+    }
+
+    // -- 4. Decompress and upload sample+instrument bin -----------------------
+    let decompPtr = sys.malloc(SAMPLEINST_SIZE)
+    gzip.decompFromTo(filePtr + pos, compressedSize, decompPtr)
+    pos += compressedSize
+
+    // Write decompressed data to peripheral memory (backwards addressing:
+    // peripheral byte k lives at memBase - k).
+    for (let i = 0; i < SAMPLEINST_SIZE; i++) {
+        // TODO use sys.memcpy
+        sys.poke(memBase - i, sys.peek(decompPtr + i))
+    }
+    sys.free(decompPtr)
+
+    // -- 5. Parse song-table entry for the requested song --------------------
+    let entryOff   = pos + songIndex * TAUD_SONG_ENTRY
+    let songOffset = _peekU32LE(filePtr, entryOff)
+    let numVoices  = sys.peek(filePtr + entryOff + 4) & 0xFF
+    let numPatsLo  = sys.peek(filePtr + entryOff + 5) & 0xFF
+    let numPatsHi  = sys.peek(filePtr + entryOff + 6) & 0xFF
+    let bpmStored  = sys.peek(filePtr + entryOff + 7) & 0xFF
+    let tickRate   = sys.peek(filePtr + entryOff + 8) & 0xFF
+    let mixerflags = sys.peek(filePtr + entryOff + 15) & 0xFF
+    let songGlobalVolume = sys.peek(filePtr + entryOff + 16) & 0xFF
+    let songMixingVolume = sys.peek(filePtr + entryOff + 17) & 0xFF
+    let patBinCompSize   = _peekU32LE(filePtr, entryOff + 18)
+    let cueSheetCompSize = _peekU32LE(filePtr, entryOff + 22)
+
+    let bpm        = bpmStored + 24
+    let patsToLoad = numPatsLo | (numPatsHi << 8)
+
+    // -- 6. Decompress + upload patterns --------------------------------------
+    let patBinSize  = patsToLoad * PATTERN_SIZE
+    let patBinPtr   = sys.malloc(patBinSize)
+    gzip.decompFromTo(filePtr + songOffset, patBinCompSize, patBinPtr)
+
+    let patBytes = new Array(PATTERN_SIZE)
+    for (let p = 0; p < patsToLoad; p++) {
+        for (let k = 0; k < PATTERN_SIZE; k++)
+            patBytes[k] = sys.peek(patBinPtr + p * PATTERN_SIZE + k) & 0xFF
+        audio.uploadPattern(p, patBytes)
+    }
+    sys.free(patBinPtr)
+
+    // -- 7. Decompress + upload cue sheet -------------------------------------
+    let cueSheetSize = NUM_CUES * CUE_SIZE
+    let cueSheetPtr  = sys.malloc(cueSheetSize)
+    gzip.decompFromTo(filePtr + songOffset + patBinCompSize, cueSheetCompSize, cueSheetPtr)
+
+    let cueBytes = new Array(CUE_SIZE)
+    for (let c = 0; c < NUM_CUES; c++) {
+        for (let k = 0; k < CUE_SIZE; k++)
+            cueBytes[k] = sys.peek(cueSheetPtr + c * CUE_SIZE + k) & 0xFF
+        audio.uploadCue(c, cueBytes)
+    }
+    sys.free(cueSheetPtr)
+
+    // -- 8. Configure playhead ------------------------------------------------
+    audio.setTrackerMode(playhead)
+    audio.setBPM(playhead, bpm)
+    audio.setTickRate(playhead, tickRate > 0 ? tickRate : 6)
+    audio.setTrackerMixerFlags(playhead, mixerflags)
+    audio.setSongGlobalVolume(playhead, songGlobalVolume)
+    audio.setSongMixingVolume(playhead, songMixingVolume)
+
+
+    fileHandle.close()
+    sys.free(filePtr)
+}
+
+// ── captureTrackerDataToFile ────────────────────────────────────────────────
+
+/**
+ * Dump the current tracker hardware state (sample bin, instruments, patterns
+ * in bank 0, cue sheet) to a single-song Taud file.  BPM and tick-rate are
+ * taken from playhead 0.
+ *
+ * @param outFile Full path with drive letter, e.g. "A:/music/out.taud"
+ */
+function captureTrackerDataToFile(outFile) {
+    const drive    = outFile[0].toUpperCase()
+    const diskPath = outFile.substring(2)
+
+    const memBase  = audio.getMemAddr()
+    const baseAddr = audio.getBaseAddr()
+
+    // -- 1. Compress sample+instrument bin ------------------------------------
+    // sys.memcpy(negative_src, positive_dst, len) copies peripheral byte k from
+    // (memBase - k) into (sampleInstBuf + k).
+    let sampleInstBuf = sys.malloc(SAMPLEINST_SIZE)
+    sys.memcpy(memBase, sampleInstBuf, SAMPLEINST_SIZE)
+
+    let compBuf       = sys.malloc(SAMPLEINST_SIZE + 4096)  // headroom for incompressible data
+    let compressedSize = gzip.compFromTo(sampleInstBuf, SAMPLEINST_SIZE, compBuf)
+    sys.free(sampleInstBuf)
+
+    // -- 2. Find last non-empty pattern in bank 0 (all-zero = uninitialized) --
+    let numPatsActual = 0
+    outer: for (let p = NUM_PATTERNS_MAX - 1; p >= 0; p--) {
+        let patBase = 131072 + p * PATTERN_SIZE  // offset within peripheral memory space
+        for (let k = 0; k < PATTERN_SIZE; k++) {
+            if ((sys.peek(memBase - (patBase + k)) & 0xFF) !== 0) {
+                numPatsActual = p + 1
+                break outer
+            }
+        }
+    }
+    if (numPatsActual === 0) numPatsActual = 1  // always emit at least one pattern slot
+
+    let numPats    = numPatsActual  // Uint16, 1-65535
+    let patsToSave = numPatsActual
+
+    // -- 3. BPM / tick-rate / volumes from playhead 0 -------------------------
+    let bpm      = audio.getBPM(0)      || 125
+    let tickRate = audio.getTickRate(0) || 6
+    let bpmStored = (bpm - 24) & 0xFF
+    let songGlobalVolume = audio.getSongGlobalVolume(0)
+    let songMixingVolume = audio.getSongMixingVolume(0)
+    if (songGlobalVolume === undefined || songGlobalVolume === null) songGlobalVolume = 0x80
+    if (songMixingVolume === undefined || songMixingVolume === null) songMixingVolume = 0x80
+
+    // -- 4. Compress pattern bin ----------------------------------------------
+    let patBinSize = patsToSave * PATTERN_SIZE
+    let patBuf     = sys.malloc(patBinSize)
+    sys.memcpy(memBase - 131072, patBuf, patBinSize)
+
+    let patCompBuf = sys.malloc(patBinSize + 4096)
+    let patCompSize = gzip.compFromTo(patBuf, patBinSize, patCompBuf)
+    sys.free(patBuf)
+
+    // -- 5. Compress cue sheet ------------------------------------------------
+    // Cue entry c, byte k is at MMIO address 32768 + c*32 + k,
+    // accessed as sys.peek(baseAddr − (32768 + c*32 + k)).
+    let cueSheetSize = NUM_CUES * CUE_SIZE
+    let cueBuf = sys.malloc(cueSheetSize)
+    for (let c = 0; c < NUM_CUES; c++) {
+        let cueOff = 32768 + c * CUE_SIZE
+        for (let k = 0; k < CUE_SIZE; k++)
+            sys.poke(cueBuf + c * CUE_SIZE + k,
+                sys.peek(baseAddr - (cueOff + k)) & 0xFF)
+    }
+
+    let cueCompBuf  = sys.malloc(cueSheetSize + 4096)
+    let cueCompSize = gzip.compFromTo(cueBuf, cueSheetSize, cueCompBuf)
+    sys.free(cueBuf)
+
+    // -- 6. Compute song offset (absolute from file start) --------------------
+    // Layout: header(32) + compressed(compressedSize) + songTable(1 × TAUD_SONG_ENTRY)
+    let songOffset = TAUD_HEADER_SIZE + compressedSize + 1 * TAUD_SONG_ENTRY
+
+    // -- 7. Build header byte array (32 bytes) --------------------------------
+    let sigBytes = new Array(14)
+    for (let i = 0; i < 14; i++)
+        sigBytes[i] = i < CAPTURE_SIGNATURE.length ? CAPTURE_SIGNATURE.charCodeAt(i) : 0
+
+    let header = [
+        // Magic (8)
+        0x1F, 0x54, 0x53, 0x56, 0x4D, 0x61, 0x75, 0x64,
+        // version, numSongs
+        TAUD_VERSION, 1,
+        // compressedSize uint32 LE (4) -- sample+inst bin
+        (compressedSize        ) & 0xFF,
+        (compressedSize >>>  8) & 0xFF,
+        (compressedSize >>> 16) & 0xFF,
+        (compressedSize >>> 24) & 0xFF,
+        // project data offset (4) -- not emitted
+        0x00, 0x00, 0x00, 0x00,
+    ].concat(sigBytes)  // 8 + 2 + 4 + 4 + 14 = 32 bytes
+
+    // -- 8. Build song-table row (32 bytes) -----------------------------------
+    let songTable = [
+        (songOffset        ) & 0xFF,
+        (songOffset >>>  8) & 0xFF,
+        (songOffset >>> 16) & 0xFF,
+        (songOffset >>> 24) & 0xFF,
+        20,                                    // numVoices
+        numPats & 0xFF, (numPats >>> 8) & 0xFF, // numPatterns Uint16 LE
+        bpmStored,                             // BPM with −24 bias
+        tickRate,                              // initial tick-rate
+        0x00,0xA0,                             // basenote (0xA000 -- C9)
+        0x00,0xAC,0x02,0x46,                   // basefreq (8363 Hz)
+        sys.peek(baseAddr - 7),                // mixer flags
+        songGlobalVolume & 0xFF,               // global volume
+        songMixingVolume & 0xFF,               // mixing volume
+        // pattern bin compressed size (4)
+        (patCompSize        ) & 0xFF,
+        (patCompSize >>>  8) & 0xFF,
+        (patCompSize >>> 16) & 0xFF,
+        (patCompSize >>> 24) & 0xFF,
+        // cue sheet compressed size (4)
+        (cueCompSize        ) & 0xFF,
+        (cueCompSize >>>  8) & 0xFF,
+        (cueCompSize >>> 16) & 0xFF,
+        (cueCompSize >>> 24) & 0xFF,
+        // reserved (6)
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    ]
+
+    // -- 9. Write header (creates / truncates file) ---------------------------
+    const fileHandle = files.open(outFile)
+    fileHandle.bwrite(header)
+
+    // -- 10. Append compressed sample+inst bin --------------------------------
+    fileHandle.pwrite(compBuf, compressedSize, TAUD_HEADER_SIZE)
+    sys.free(compBuf)
+
+    // -- 11. Write song table -------------------------------------------------
+    fileHandle.bwrite(songTable)
+
+    // -- 12. Append compressed pattern bin ------------------------------------
+    fileHandle.pwrite(patCompBuf, patCompSize,
+        TAUD_HEADER_SIZE + compressedSize + songTable.length)
+    sys.free(patCompBuf)
+
+    // -- 13. Append compressed cue sheet --------------------------------------
+    fileHandle.pwrite(cueCompBuf, cueCompSize,
+        TAUD_HEADER_SIZE + compressedSize + songTable.length + patCompSize)
+    sys.free(cueCompBuf)
+
+
+    fileHandle.flush(); fileHandle.close()
+}
+
+exports = { uploadTaudFile, captureTrackerDataToFile }

assets/disk0/tvdos/include/wintex.mjs

@@ -1,3 +1,8 @@
+/**
+ * WinTex — TUI window management and renderer
+ * @author CuriousTorvald
+ */
+
 class WindowObject {
 
     constructor(x, y, w, h, inputProcessor, drawContents, title, drawFrame) {

assets/disk0/tvdos/tuidev/Makefile

@@ -0,0 +1,6 @@
+CC = gcc
+CFLAGS = -std=c99 -O3 -Wall -Wextra -Ofast -D_GNU_SOURCE
+
+font_rom_builder:
+	rm -f font_rom_builder
+	$(CC) $(CFLAGS) font_rom_builder.c -o font_rom_builder

assets/disk0/tvdos/tuidev/font_rom_builder.c

@@ -0,0 +1,202 @@
+/*
+ * font_rom_builder.c
+ * Build TSVM 7x14 font ROM from human-readable images (.png, .tga)
+ *
+ * Input: Image with no gaps between characters (7x14 pixels per glyph)
+ * Output: TSVM-compatible font ROM file(s) padded to 1920 bytes
+ *
+ * Usage:
+ *   gcc -O2 -std=c99 -Wall font_rom_builder.c -o font_rom_builder
+ *   ./font_rom_builder <input.png|tga> <output_prefix>
+ *
+ * For 128-char images: outputs <output_prefix>_high.chr
+ * For 256-char images: outputs <output_prefix>_low.chr and <output_prefix>_high.chr
+ *
+ * Image layout:
+ *   - 128 chars: 16 columns × 8 rows = 112×112 pixels
+ *   - 256 chars: 16 columns × 16 rows = 112×224 pixels
+ *             or 32 columns × 8 rows = 224×112 pixels
+ *
+ * ROM format:
+ *   - Each glyph: 14 bytes (one byte per row)
+ *   - Bit 6 = leftmost pixel, Bit 0 = rightmost pixel
+ *   - Each ROM padded to 1920 bytes
+ */
+
+#define _POSIX_C_SOURCE 200809L
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdint.h>
+
+#define GLYPH_W 7
+#define GLYPH_H 14
+#define GLYPH_BYTES 14
+#define ROM_PADDED_SIZE 1920
+
+static void die(const char *msg) {
+    fprintf(stderr, "Error: %s\n", msg);
+    exit(1);
+}
+
+static void write_rom(const char *filename, const uint8_t *glyphs, int glyph_count) {
+    FILE *out = fopen(filename, "wb");
+    if (!out) {
+        fprintf(stderr, "Failed to open output file: %s\n", filename);
+        exit(1);
+    }
+
+    // Write glyph data
+    size_t data_size = glyph_count * GLYPH_BYTES;
+    fwrite(glyphs, 1, data_size, out);
+
+    // Pad to 1920 bytes
+    if (data_size < ROM_PADDED_SIZE) {
+        size_t padding = ROM_PADDED_SIZE - data_size;
+        uint8_t *pad = calloc(padding, 1);
+        fwrite(pad, 1, padding, out);
+        free(pad);
+        fprintf(stderr, "  Wrote %zu bytes + %zu bytes padding = %d bytes total\n",
+                data_size, padding, ROM_PADDED_SIZE);
+    } else {
+        fprintf(stderr, "  Wrote %zu bytes (no padding needed)\n", data_size);
+    }
+
+    fclose(out);
+    fprintf(stderr, "  Output: %s\n", filename);
+}
+
+int main(int argc, char **argv) {
+    if (argc < 3) {
+        fprintf(stderr, "Usage: %s <input.png|tga> <output_prefix>\n", argv[0]);
+        fprintf(stderr, "\n");
+        fprintf(stderr, "Converts human-readable font images to TSVM font ROM format.\n");
+        fprintf(stderr, "\n");
+        fprintf(stderr, "Input requirements:\n");
+        fprintf(stderr, "  - Image with no gaps between characters\n");
+        fprintf(stderr, "  - Each character is 7x14 pixels\n");
+        fprintf(stderr, "  - 128 chars: typically 112x112 (16 cols × 8 rows)\n");
+        fprintf(stderr, "  - 256 chars: typically 112x224 (16 cols × 16 rows)\n");
+        fprintf(stderr, "\n");
+        fprintf(stderr, "Output:\n");
+        fprintf(stderr, "  - 128 chars: <prefix>_high.chr (high ROM only)\n");
+        fprintf(stderr, "  - 256 chars: <prefix>_low.chr + <prefix>_high.chr\n");
+        fprintf(stderr, "  - Each ROM padded to 1920 bytes\n");
+        return 1;
+    }
+
+    const char *input_path = argv[1];
+    const char *output_prefix = argv[2];
+
+    // Get image dimensions using ImageMagick identify
+    char cmd[1024];
+    snprintf(cmd, sizeof(cmd), "identify -format '%%w %%h' \"%s\" 2>/dev/null", input_path);
+
+    FILE *pipe = popen(cmd, "r");
+    if (!pipe) die("Failed to run 'identify' command (ImageMagick required)");
+
+    int img_w = 0, img_h = 0;
+    if (fscanf(pipe, "%d %d", &img_w, &img_h) != 2) {
+        pclose(pipe);
+        die("Failed to read image dimensions (is ImageMagick installed?)");
+    }
+    pclose(pipe);
+
+    fprintf(stderr, "Input: %s (%dx%d)\n", input_path, img_w, img_h);
+
+    // Calculate grid dimensions
+    int cols = img_w / GLYPH_W;
+    int rows = img_h / GLYPH_H;
+    int total_chars = cols * rows;
+
+    if (img_w % GLYPH_W != 0 || img_h % GLYPH_H != 0) {
+        fprintf(stderr, "Warning: Image dimensions not evenly divisible by %dx%d\n",
+                GLYPH_W, GLYPH_H);
+    }
+
+    fprintf(stderr, "Grid: %d columns × %d rows = %d characters\n", cols, rows, total_chars);
+
+    // Validate character count
+    if (total_chars != 128 && total_chars != 256) {
+        fprintf(stderr, "Error: Expected 128 or 256 characters, got %d\n", total_chars);
+        fprintf(stderr, "  For 128 chars: use 112x112 (16×8) or similar layout\n");
+        fprintf(stderr, "  For 256 chars: use 112x224 (16×16) or 224x112 (32×8)\n");
+        return 1;
+    }
+
+    // Read image as grayscale using ImageMagick convert
+    // IMPORTANT: Flatten alpha onto black background first, so transparent pixels become black
+    size_t img_size = img_w * img_h;
+    uint8_t *img_data = malloc(img_size);
+    if (!img_data) die("Memory allocation failed");
+
+    snprintf(cmd, sizeof(cmd),
+             "convert \"%s\" -background black -alpha remove -colorspace Gray -depth 8 gray:- 2>/dev/null",
+             input_path);
+
+    pipe = popen(cmd, "r");
+    if (!pipe) die("Failed to run 'convert' command (ImageMagick required)");
+
+    if (fread(img_data, 1, img_size, pipe) != img_size) {
+        pclose(pipe);
+        die("Failed to read image data from ImageMagick");
+    }
+    pclose(pipe);
+
+    fprintf(stderr, "Read %zu bytes of grayscale data\n", img_size);
+
+    // Extract glyphs
+    uint8_t *glyphs = calloc(total_chars, GLYPH_BYTES);
+    if (!glyphs) die("Memory allocation failed");
+
+    for (int gy = 0; gy < rows; gy++) {
+        for (int gx = 0; gx < cols; gx++) {
+            int glyph_idx = gy * cols + gx;
+            uint8_t *glyph = &glyphs[glyph_idx * GLYPH_BYTES];
+
+            for (int row = 0; row < GLYPH_H; row++) {
+                uint8_t byte = 0;
+                for (int col = 0; col < GLYPH_W; col++) {
+                    int px = gx * GLYPH_W + col;
+                    int py = gy * GLYPH_H + row;
+                    uint8_t pixel = img_data[py * img_w + px];
+
+                    // Threshold: >= 128 is foreground (white/lit)
+                    int is_set = (pixel >= 128) ? 1 : 0;
+
+                    // Pack: bit 6 = leftmost, bit 0 = rightmost
+                    if (is_set) {
+                        byte |= (1u << (6 - col));
+                    }
+                }
+                glyph[row] = byte;
+            }
+        }
+    }
+
+    free(img_data);
+    fprintf(stderr, "Extracted %d glyphs\n", total_chars);
+
+    // Write output ROM file(s)
+    char out_path[1024];
+
+    if (total_chars == 128) {
+        // High ROM only (chars 128-255)
+        snprintf(out_path, sizeof(out_path), "%s.chr", output_prefix);
+        fprintf(stderr, "\nWriting high ROM (128 chars):\n");
+        write_rom(out_path, glyphs, 128);
+    } else {
+        // 256 chars: low ROM (0-127) and high ROM (128-255)
+        snprintf(out_path, sizeof(out_path), "%s_low.chr", output_prefix);
+        fprintf(stderr, "\nWriting low ROM (chars 0-127):\n");
+        write_rom(out_path, glyphs, 128);
+
+        snprintf(out_path, sizeof(out_path), "%s_high.chr", output_prefix);
+        fprintf(stderr, "\nWriting high ROM (chars 128-255):\n");
+        write_rom(out_path, &glyphs[128 * GLYPH_BYTES], 128);
+    }
+
+    free(glyphs);
+    fprintf(stderr, "\nDone.\n");
+    return 0;
+}

buildapp/build_app_linux_arm.sh

@@ -22,6 +22,7 @@ cp -r "../out/$RUNTIME" $DESTDIR/
 
 # Copy over all the assets and a jarfile
 cp -r "../out/TerranBASIC.jar" $DESTDIR/
+cp "../lib/compiler-23.1.10.jar" "../lib/compiler-management-23.1.10.jar" "../lib/truffle-compiler-23.1.10.jar" "../lib/truffle-api-23.1.10.jar" "../lib/truffle-runtime-23.1.10.jar" "../lib/polyglot-23.1.10.jar" "../lib/collections-23.1.10.jar" "../lib/word-23.1.10.jar" "../lib/nativeimage-23.1.10.jar" "../lib/jniutils-23.1.10.jar" $DESTDIR/
 
 # Pack everything to AppImage
 ARCH=arm_aarch64 "./$APPIMAGETOOL" $DESTDIR "out/$DESTDIR.AppImage" || { echo 'Building AppImage failed' >&2; exit 1; }

buildapp/build_app_linux_x86.sh

@@ -22,6 +22,7 @@ cp -r "../out/$RUNTIME" $DESTDIR/
 
 # Copy over all the assets and a jarfile
 cp -r "../out/TerranBASIC.jar" $DESTDIR/
+cp "../lib/compiler-23.1.10.jar" "../lib/compiler-management-23.1.10.jar" "../lib/truffle-compiler-23.1.10.jar" "../lib/truffle-api-23.1.10.jar" "../lib/truffle-runtime-23.1.10.jar" "../lib/polyglot-23.1.10.jar" "../lib/collections-23.1.10.jar" "../lib/word-23.1.10.jar" "../lib/nativeimage-23.1.10.jar" "../lib/jniutils-23.1.10.jar" $DESTDIR/
 
 # Pack everything to AppImage
 "./$APPIMAGETOOL" $DESTDIR "out/$DESTDIR.AppImage" || { echo 'Building AppImage failed' >&2; exit 1; }

buildapp/build_app_mac_arm.sh

@@ -23,5 +23,6 @@ cp -r "../out/$RUNTIME" $DESTDIR/Contents/MacOS/
 
 # Copy over all the assets and a jarfile
 cp -r "../out/TerranBASIC.jar" $DESTDIR/Contents/MacOS/
+cp "../lib/compiler-23.1.10.jar" "../lib/compiler-management-23.1.10.jar" "../lib/truffle-compiler-23.1.10.jar" "../lib/truffle-api-23.1.10.jar" "../lib/truffle-runtime-23.1.10.jar" "../lib/polyglot-23.1.10.jar" "../lib/collections-23.1.10.jar" "../lib/word-23.1.10.jar" "../lib/nativeimage-23.1.10.jar" "../lib/jniutils-23.1.10.jar" $DESTDIR/Contents/MacOS/
 
 echo "Build successful: $DESTDIR"

buildapp/build_app_mac_x86.sh

@@ -23,5 +23,6 @@ cp -r "../out/$RUNTIME" $DESTDIR/Contents/MacOS/
 
 # Copy over all the assets and a jarfile
 cp -r "../out/TerranBASIC.jar" $DESTDIR/Contents/MacOS/
+cp "../lib/compiler-23.1.10.jar" "../lib/compiler-management-23.1.10.jar" "../lib/truffle-compiler-23.1.10.jar" "../lib/truffle-api-23.1.10.jar" "../lib/truffle-runtime-23.1.10.jar" "../lib/polyglot-23.1.10.jar" "../lib/collections-23.1.10.jar" "../lib/word-23.1.10.jar" "../lib/nativeimage-23.1.10.jar" "../lib/jniutils-23.1.10.jar" $DESTDIR/Contents/MacOS/
 
 echo "Build successful: $DESTDIR"

buildapp/build_app_windows_x86.sh

@@ -18,6 +18,7 @@ cp -r "../out/$RUNTIME" $DESTDIR/
 
 # Copy over all the assets and a jarfile
 cp -r "../out/TerranBASIC.jar" $DESTDIR/
+cp "../lib/compiler-23.1.10.jar" "../lib/compiler-management-23.1.10.jar" "../lib/truffle-compiler-23.1.10.jar" "../lib/truffle-api-23.1.10.jar" "../lib/truffle-runtime-23.1.10.jar" "../lib/polyglot-23.1.10.jar" "../lib/collections-23.1.10.jar" "../lib/word-23.1.10.jar" "../lib/nativeimage-23.1.10.jar" "../lib/jniutils-23.1.10.jar" $DESTDIR/
 
 # Temporary solution: zip everything
 zip -r -9 -l "out/$DESTDIR.zip" $DESTDIR

buildapp/tbaslinux_arm/AppRun

@@ -1,3 +1,4 @@
 #!/bin/bash
 cd "${0%/*}"
-./runtime-linux-arm/bin/java -Xms128M -Xmx2G -Dswing.aatext=true -Dawt.useSystemAAFontSettings=lcd -jar ./TerranBASIC.jar
+GRAAL_MODULE_PATH=compiler-23.1.10.jar:compiler-management-23.1.10.jar:truffle-compiler-23.1.10.jar:truffle-api-23.1.10.jar:truffle-runtime-23.1.10.jar:polyglot-23.1.10.jar:collections-23.1.10.jar:word-23.1.10.jar:nativeimage-23.1.10.jar:jniutils-23.1.10.jar
+./runtime-linux-arm/bin/java --upgrade-module-path=$GRAAL_MODULE_PATH -XX:+UnlockExperimentalVMOptions -XX:+EnableJVMCI --add-exports=java.base/jdk.internal.misc=jdk.internal.vm.compiler -Xms128M -Xmx2G -Dswing.aatext=true -Dawt.useSystemAAFontSettings=lcd -jar ./TerranBASIC.jar

buildapp/tbaslinux_x86/AppRun

@@ -1,3 +1,4 @@
 #!/bin/bash
 cd "${0%/*}"
-./runtime-linux-x86/bin/java -Xms128M -Xmx2G -Dswing.aatext=true -Dawt.useSystemAAFontSettings=lcd -jar ./TerranBASIC.jar
+GRAAL_MODULE_PATH=compiler-23.1.10.jar:compiler-management-23.1.10.jar:truffle-compiler-23.1.10.jar:truffle-api-23.1.10.jar:truffle-runtime-23.1.10.jar:polyglot-23.1.10.jar:collections-23.1.10.jar:word-23.1.10.jar:nativeimage-23.1.10.jar:jniutils-23.1.10.jar
+./runtime-linux-x86/bin/java --upgrade-module-path=$GRAAL_MODULE_PATH -XX:+UnlockExperimentalVMOptions -XX:+EnableJVMCI --add-exports=java.base/jdk.internal.misc=jdk.internal.vm.compiler -Xms128M -Xmx2G -Dswing.aatext=true -Dawt.useSystemAAFontSettings=lcd -jar ./TerranBASIC.jar

buildapp/tbasmac_arm/TerranBASIC.sh

@@ -1,3 +1,4 @@
 #!/bin/bash
 cd "${0%/*}"
-./runtime-osx-arm/bin/java -XstartOnFirstThread -Xms128M -Xmx2G -jar ./TerranBASIC.jar
+GRAAL_MODULE_PATH=compiler-23.1.10.jar:compiler-management-23.1.10.jar:truffle-compiler-23.1.10.jar:truffle-api-23.1.10.jar:truffle-runtime-23.1.10.jar:polyglot-23.1.10.jar:collections-23.1.10.jar:word-23.1.10.jar:nativeimage-23.1.10.jar:jniutils-23.1.10.jar
+./runtime-osx-arm/bin/java --upgrade-module-path=$GRAAL_MODULE_PATH -XX:+UnlockExperimentalVMOptions -XX:+EnableJVMCI --add-exports=java.base/jdk.internal.misc=jdk.internal.vm.compiler -XstartOnFirstThread -Xms128M -Xmx2G -jar ./TerranBASIC.jar

buildapp/tbasmac_x86/TerranBASIC.sh

@@ -1,3 +1,4 @@
 #!/bin/bash
 cd "${0%/*}"
-./runtime-osx-x86/bin/java -XstartOnFirstThread -Xms128M -Xmx2G -jar ./TerranBASIC.jar
+GRAAL_MODULE_PATH=compiler-23.1.10.jar:compiler-management-23.1.10.jar:truffle-compiler-23.1.10.jar:truffle-api-23.1.10.jar:truffle-runtime-23.1.10.jar:polyglot-23.1.10.jar:collections-23.1.10.jar:word-23.1.10.jar:nativeimage-23.1.10.jar:jniutils-23.1.10.jar
+./runtime-osx-x86/bin/java --upgrade-module-path=$GRAAL_MODULE_PATH -XX:+UnlockExperimentalVMOptions -XX:+EnableJVMCI --add-exports=java.base/jdk.internal.misc=jdk.internal.vm.compiler -XstartOnFirstThread -Xms128M -Xmx2G -jar ./TerranBASIC.jar

buildapp/tbaswindows_x86/TerranBASIC.bat

@@ -1,2 +1,3 @@
 cd /D "%~dp0"
-.\runtime-windows-x86\bin\java -Xms128M -Xmx2G -jar .\TerranBASIC.jar
+set GRAAL_MODULE_PATH=compiler-23.1.10.jar;compiler-management-23.1.10.jar;truffle-compiler-23.1.10.jar;truffle-api-23.1.10.jar;truffle-runtime-23.1.10.jar;polyglot-23.1.10.jar;collections-23.1.10.jar;word-23.1.10.jar;nativeimage-23.1.10.jar;jniutils-23.1.10.jar
+.\runtime-windows-x86\bin\java --upgrade-module-path=%GRAAL_MODULE_PATH% -XX:+UnlockExperimentalVMOptions -XX:+EnableJVMCI --add-exports=java.base/jdk.internal.misc=jdk.internal.vm.compiler -Xms128M -Xmx2G -jar .\TerranBASIC.jar

doc/implementation.tex

@@ -662,7 +662,7 @@ TODO
 \endlastfoot
 \centering
 \begin{tabulary}{\textwidth}{rl}
-{\ttfamily 0} & {\ttfamily \#000F} \\
+{\ttfamily 0} & {\ttfamily \#0007} \\
 {\ttfamily 1} & {\ttfamily \#004F} \\
 {\ttfamily 2} & {\ttfamily \#008F} \\
 {\ttfamily 3} & {\ttfamily \#00BF} \\

ipf_encoder/Makefile

@@ -0,0 +1,81 @@
+# Makefile for iPF (TSVM Interchangeable Picture Format) Encoder
+# Created by CuriousTorvald and Claude on 2025-12-19.
+
+CC = gcc
+CFLAGS = -std=c99 -Wall -Wextra -O2 -D_GNU_SOURCE
+DBGFLAGS =
+PREFIX = /usr/local
+
+# Zstd flags (use pkg-config if available, fallback for cross-platform compatibility)
+ZSTD_CFLAGS = $(shell pkg-config --cflags libzstd 2>/dev/null || echo "")
+ZSTD_LIBS = $(shell pkg-config --libs libzstd 2>/dev/null || echo "-lzstd")
+LIBS = -lm $(ZSTD_LIBS)
+
+# Targets
+TARGETS = encoder_ipf decoder_ipf
+
+# Build all (default)
+all: $(TARGETS)
+
+encoder_ipf: encoder_ipf.c
+	rm -f encoder_ipf
+	$(CC) $(CFLAGS) $(ZSTD_CFLAGS) -o encoder_ipf encoder_ipf.c $(LIBS)
+	@echo "iPF encoder built: encoder_ipf"
+
+decoder_ipf: decoder_ipf.c
+	rm -f decoder_ipf
+	$(CC) $(CFLAGS) $(ZSTD_CFLAGS) -o decoder_ipf decoder_ipf.c $(LIBS)
+	@echo "iPF decoder built: decoder_ipf"
+
+# Build with debug symbols
+debug: CFLAGS += -g -DDEBUG -fsanitize=address -fno-omit-frame-pointer
+debug: DBGFLAGS += -fsanitize=address -fno-omit-frame-pointer
+debug: clean $(TARGETS)
+
+# Build with optimizations
+release: CFLAGS = -std=c99 -Wall -Wextra -O3 -D_GNU_SOURCE -march=native
+release: clean $(TARGETS)
+
+# Clean build artifacts
+clean:
+	rm -f $(TARGETS) *.o
+
+# Install
+install: $(TARGETS)
+	cp encoder_ipf $(PREFIX)/bin/
+	cp decoder_ipf $(PREFIX)/bin/
+
+# Check for required dependencies
+check-deps:
+	@echo "Checking dependencies..."
+	@pkg-config --exists libzstd || (echo "Error: libzstd-dev not found. Install libzstd-dev or equivalent" && exit 1)
+	@which ffmpeg >/dev/null 2>&1 || (echo "Error: ffmpeg not found in PATH" && exit 1)
+	@which ffprobe >/dev/null 2>&1 || (echo "Error: ffprobe not found in PATH" && exit 1)
+	@echo "All dependencies found."
+
+# Help
+help:
+	@echo "iPF (TSVM Interchangeable Picture Format) Tools"
+	@echo ""
+	@echo "Targets:"
+	@echo "  all          - Build encoder and decoder (default)"
+	@echo "  encoder_ipf  - Build encoder only"
+	@echo "  decoder_ipf  - Build decoder only"
+	@echo "  debug        - Build with debug symbols and AddressSanitizer"
+	@echo "  release      - Build with full optimizations"
+	@echo "  clean        - Remove build artifacts"
+	@echo "  install      - Install to /usr/local/bin"
+	@echo "  check-deps   - Check for required dependencies"
+	@echo "  help         - Show this help"
+	@echo ""
+	@echo "Requirements:"
+	@echo "  - GCC with C99 support"
+	@echo "  - libzstd-dev (Zstd compression library)"
+	@echo "  - FFmpeg (for image encoding/decoding)"
+	@echo ""
+	@echo "Usage:"
+	@echo "  make                                          # Build all"
+	@echo "  ./encoder_ipf -i input.png -o output.ipf      # Encode"
+	@echo "  ./decoder_ipf -i output.ipf -o decoded.png    # Decode"
+
+.PHONY: all clean install check-deps help debug release

ipf_encoder/decoder_ipf.c

@@ -0,0 +1,592 @@
+/**
+ * iPF Decoder - TSVM Interchangeable Picture Format Decoder
+ *
+ * Decodes iPF format (Type 1 or Type 2) images to standard formats via FFmpeg.
+ *
+ * Created by CuriousTorvald and Claude on 2025-12-19.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include <math.h>
+#include <getopt.h>
+#include <zstd.h>
+
+// =============================================================================
+// Constants
+// =============================================================================
+
+#define IPF_MAGIC "\x1F\x54\x53\x56\x4D\x69\x50\x46"  // "\x1FTSVMiPF"
+#define IPF_HEADER_SIZE 28  // 8 magic + 2 width + 2 height + 1 flags + 1 type + 10 reserved + 4 uncompressed
+
+#define IPF_TYPE_1 0  // 4:2:0 chroma subsampling
+#define IPF_TYPE_2 1  // 4:2:2 chroma subsampling
+
+#define IPF_FLAG_ALPHA       0x01
+#define IPF_FLAG_ZSTD        0x10
+#define IPF_FLAG_PROGRESSIVE 0x80
+
+#define MAX_PATH 4096
+
+// =============================================================================
+// Structures
+// =============================================================================
+
+typedef struct {
+    uint16_t width;
+    uint16_t height;
+    uint8_t flags;
+    uint8_t type;
+    uint32_t uncompressed_size;
+} ipf_header_t;
+
+typedef struct {
+    char *input_file;
+    char *output_file;
+    int verbose;
+    int raw_output;  // Output raw RGB instead of using FFmpeg
+} decoder_config_t;
+
+// =============================================================================
+// Utility Functions
+// =============================================================================
+
+static void print_usage(const char *program) {
+    printf("iPF Decoder - TSVM Interchangeable Picture Format\n");
+    printf("\nUsage: %s -i input.ipf -o output.png [options]\n\n", program);
+    printf("Required:\n");
+    printf("  -i, --input FILE         Input iPF file\n");
+    printf("  -o, --output FILE        Output image file (any format FFmpeg supports)\n");
+    printf("\nOptions:\n");
+    printf("  --raw                    Output raw RGB24/RGBA data instead of image file\n");
+    printf("  -v, --verbose            Verbose output\n");
+    printf("  -h, --help               Show this help\n");
+    printf("\nExamples:\n");
+    printf("  %s -i photo.ipf -o photo.png\n", program);
+    printf("  %s -i logo.ipf -o logo.jpg -v\n", program);
+}
+
+static float clampf(float v, float lo, float hi) {
+    return v < lo ? lo : (v > hi ? hi : v);
+}
+
+// =============================================================================
+// iPF File Reading
+// =============================================================================
+
+static int read_ipf_header(FILE *fp, ipf_header_t *header) {
+    uint8_t magic[8];
+
+    if (fread(magic, 1, 8, fp) != 8) {
+        fprintf(stderr, "Error: Failed to read magic\n");
+        return -1;
+    }
+
+    if (memcmp(magic, IPF_MAGIC, 8) != 0) {
+        fprintf(stderr, "Error: Invalid iPF magic\n");
+        return -1;
+    }
+
+    // Read width (uint16 LE)
+    if (fread(&header->width, 2, 1, fp) != 1) return -1;
+
+    // Read height (uint16 LE)
+    if (fread(&header->height, 2, 1, fp) != 1) return -1;
+
+    // Read flags
+    if (fread(&header->flags, 1, 1, fp) != 1) return -1;
+
+    // Read type
+    if (fread(&header->type, 1, 1, fp) != 1) return -1;
+
+    // Skip reserved (10 bytes)
+    fseek(fp, 10, SEEK_CUR);
+
+    // Read uncompressed size (uint32 LE)
+    if (fread(&header->uncompressed_size, 4, 1, fp) != 1) return -1;
+
+    return 0;
+}
+
+// =============================================================================
+// YCoCg to RGB Conversion
+// =============================================================================
+
+/**
+ * Convert YCoCg to RGB for 4 pixels sharing the same chroma.
+ * y_values: 4 Y values packed as nibbles (Y0|Y1 in low byte, Y2|Y3 in high byte style)
+ * a_values: 4 alpha values packed similarly
+ * co, cg: 4-bit chroma values [0..15]
+ *
+ * Output: fills rgb array with R,G,B[,A] values for 4 pixels
+ */
+static void ycocg_to_rgb_quad(int co, int cg, int y0, int y1, int y2, int y3,
+                              int a0, int a1, int a2, int a3,
+                              int has_alpha, uint8_t *rgb) {
+    // Convert chroma from [0..15] to [-1..1]
+    float co_f = (co - 7) / 8.0f;
+    float cg_f = (cg - 7) / 8.0f;
+
+    int ys[4] = {y0, y1, y2, y3};
+    int as[4] = {a0, a1, a2, a3};
+
+    int stride = has_alpha ? 4 : 3;
+
+    for (int i = 0; i < 4; i++) {
+        float y = ys[i] / 15.0f;
+
+        // YCoCg to RGB conversion
+        float tmp = y - cg_f / 2.0f;
+        float g = clampf(cg_f + tmp, 0.0f, 1.0f);
+        float b = clampf(tmp - co_f / 2.0f, 0.0f, 1.0f);
+        float r = clampf(b + co_f, 0.0f, 1.0f);
+
+        rgb[i * stride + 0] = (uint8_t)(r * 255.0f + 0.5f);
+        rgb[i * stride + 1] = (uint8_t)(g * 255.0f + 0.5f);
+        rgb[i * stride + 2] = (uint8_t)(b * 255.0f + 0.5f);
+
+        if (has_alpha) {
+            rgb[i * stride + 3] = (uint8_t)(as[i] * 17);  // Scale 0-15 to 0-255
+        }
+    }
+}
+
+/**
+ * Decode iPF1 block (4:2:0 chroma subsampling).
+ * Input: 12 bytes (or 20 with alpha)
+ * Output: 16 pixels in RGB24/RGBA format
+ */
+static void decode_ipf1_block(const uint8_t *block, int has_alpha, uint8_t *pixels, int stride) {
+    // Read chroma (4 values for 2x2 regions)
+    int co1 = block[0] & 0x0F;
+    int co2 = (block[0] >> 4) & 0x0F;
+    int co3 = block[1] & 0x0F;
+    int co4 = (block[1] >> 4) & 0x0F;
+
+    int cg1 = block[2] & 0x0F;
+    int cg2 = (block[2] >> 4) & 0x0F;
+    int cg3 = block[3] & 0x0F;
+    int cg4 = (block[3] >> 4) & 0x0F;
+
+    // Read Y values (16 values)
+    // Layout: [Y1|Y0|Y5|Y4], [Y3|Y2|Y7|Y6], [Y9|Y8|YD|YC], [YB|YA|YF|YE]
+    int Y[16];
+    Y[0] = block[4] & 0x0F;
+    Y[1] = (block[4] >> 4) & 0x0F;
+    Y[4] = block[5] & 0x0F;
+    Y[5] = (block[5] >> 4) & 0x0F;
+    Y[2] = block[6] & 0x0F;
+    Y[3] = (block[6] >> 4) & 0x0F;
+    Y[6] = block[7] & 0x0F;
+    Y[7] = (block[7] >> 4) & 0x0F;
+    Y[8] = block[8] & 0x0F;
+    Y[9] = (block[8] >> 4) & 0x0F;
+    Y[12] = block[9] & 0x0F;
+    Y[13] = (block[9] >> 4) & 0x0F;
+    Y[10] = block[10] & 0x0F;
+    Y[11] = (block[10] >> 4) & 0x0F;
+    Y[14] = block[11] & 0x0F;
+    Y[15] = (block[11] >> 4) & 0x0F;
+
+    // Read alpha values if present
+    int A[16];
+    if (has_alpha) {
+        A[0] = block[12] & 0x0F;
+        A[1] = (block[12] >> 4) & 0x0F;
+        A[4] = block[13] & 0x0F;
+        A[5] = (block[13] >> 4) & 0x0F;
+        A[2] = block[14] & 0x0F;
+        A[3] = (block[14] >> 4) & 0x0F;
+        A[6] = block[15] & 0x0F;
+        A[7] = (block[15] >> 4) & 0x0F;
+        A[8] = block[16] & 0x0F;
+        A[9] = (block[16] >> 4) & 0x0F;
+        A[12] = block[17] & 0x0F;
+        A[13] = (block[17] >> 4) & 0x0F;
+        A[10] = block[18] & 0x0F;
+        A[11] = (block[18] >> 4) & 0x0F;
+        A[14] = block[19] & 0x0F;
+        A[15] = (block[19] >> 4) & 0x0F;
+    } else {
+        for (int i = 0; i < 16; i++) A[i] = 15;
+    }
+
+    int channels = has_alpha ? 4 : 3;
+    uint8_t quad[16];  // 4 pixels max
+
+    // Decode 4 quads (2x2 regions), each sharing one chroma pair
+    // Top-left quad (pixels 0,1,4,5) uses co1/cg1
+    ycocg_to_rgb_quad(co1, cg1, Y[0], Y[1], Y[4], Y[5], A[0], A[1], A[4], A[5], has_alpha, quad);
+    memcpy(pixels + 0 * stride + 0 * channels, quad + 0 * channels, channels);
+    memcpy(pixels + 0 * stride + 1 * channels, quad + 1 * channels, channels);
+    memcpy(pixels + 1 * stride + 0 * channels, quad + 2 * channels, channels);
+    memcpy(pixels + 1 * stride + 1 * channels, quad + 3 * channels, channels);
+
+    // Top-right quad (pixels 2,3,6,7) uses co2/cg2
+    ycocg_to_rgb_quad(co2, cg2, Y[2], Y[3], Y[6], Y[7], A[2], A[3], A[6], A[7], has_alpha, quad);
+    memcpy(pixels + 0 * stride + 2 * channels, quad + 0 * channels, channels);
+    memcpy(pixels + 0 * stride + 3 * channels, quad + 1 * channels, channels);
+    memcpy(pixels + 1 * stride + 2 * channels, quad + 2 * channels, channels);
+    memcpy(pixels + 1 * stride + 3 * channels, quad + 3 * channels, channels);
+
+    // Bottom-left quad (pixels 8,9,12,13) uses co3/cg3
+    ycocg_to_rgb_quad(co3, cg3, Y[8], Y[9], Y[12], Y[13], A[8], A[9], A[12], A[13], has_alpha, quad);
+    memcpy(pixels + 2 * stride + 0 * channels, quad + 0 * channels, channels);
+    memcpy(pixels + 2 * stride + 1 * channels, quad + 1 * channels, channels);
+    memcpy(pixels + 3 * stride + 0 * channels, quad + 2 * channels, channels);
+    memcpy(pixels + 3 * stride + 1 * channels, quad + 3 * channels, channels);
+
+    // Bottom-right quad (pixels 10,11,14,15) uses co4/cg4
+    ycocg_to_rgb_quad(co4, cg4, Y[10], Y[11], Y[14], Y[15], A[10], A[11], A[14], A[15], has_alpha, quad);
+    memcpy(pixels + 2 * stride + 2 * channels, quad + 0 * channels, channels);
+    memcpy(pixels + 2 * stride + 3 * channels, quad + 1 * channels, channels);
+    memcpy(pixels + 3 * stride + 2 * channels, quad + 2 * channels, channels);
+    memcpy(pixels + 3 * stride + 3 * channels, quad + 3 * channels, channels);
+}
+
+/**
+ * Decode iPF2 block (4:2:2 chroma subsampling).
+ * Input: 16 bytes (or 24 with alpha)
+ * Output: 16 pixels in RGB24/RGBA format
+ */
+static void decode_ipf2_block(const uint8_t *block, int has_alpha, uint8_t *pixels, int stride) {
+    // Read chroma (8 values for horizontal pairs)
+    int co[8], cg[8];
+    co[0] = block[0] & 0x0F;
+    co[1] = (block[0] >> 4) & 0x0F;
+    co[2] = block[1] & 0x0F;
+    co[3] = (block[1] >> 4) & 0x0F;
+    co[4] = block[2] & 0x0F;
+    co[5] = (block[2] >> 4) & 0x0F;
+    co[6] = block[3] & 0x0F;
+    co[7] = (block[3] >> 4) & 0x0F;
+
+    cg[0] = block[4] & 0x0F;
+    cg[1] = (block[4] >> 4) & 0x0F;
+    cg[2] = block[5] & 0x0F;
+    cg[3] = (block[5] >> 4) & 0x0F;
+    cg[4] = block[6] & 0x0F;
+    cg[5] = (block[6] >> 4) & 0x0F;
+    cg[6] = block[7] & 0x0F;
+    cg[7] = (block[7] >> 4) & 0x0F;
+
+    // Read Y values (16 values) - same layout as iPF1
+    int Y[16];
+    Y[0] = block[8] & 0x0F;
+    Y[1] = (block[8] >> 4) & 0x0F;
+    Y[4] = block[9] & 0x0F;
+    Y[5] = (block[9] >> 4) & 0x0F;
+    Y[2] = block[10] & 0x0F;
+    Y[3] = (block[10] >> 4) & 0x0F;
+    Y[6] = block[11] & 0x0F;
+    Y[7] = (block[11] >> 4) & 0x0F;
+    Y[8] = block[12] & 0x0F;
+    Y[9] = (block[12] >> 4) & 0x0F;
+    Y[12] = block[13] & 0x0F;
+    Y[13] = (block[13] >> 4) & 0x0F;
+    Y[10] = block[14] & 0x0F;
+    Y[11] = (block[14] >> 4) & 0x0F;
+    Y[14] = block[15] & 0x0F;
+    Y[15] = (block[15] >> 4) & 0x0F;
+
+    // Read alpha values if present
+    int A[16];
+    if (has_alpha) {
+        A[0] = block[16] & 0x0F;
+        A[1] = (block[16] >> 4) & 0x0F;
+        A[4] = block[17] & 0x0F;
+        A[5] = (block[17] >> 4) & 0x0F;
+        A[2] = block[18] & 0x0F;
+        A[3] = (block[18] >> 4) & 0x0F;
+        A[6] = block[19] & 0x0F;
+        A[7] = (block[19] >> 4) & 0x0F;
+        A[8] = block[20] & 0x0F;
+        A[9] = (block[20] >> 4) & 0x0F;
+        A[12] = block[21] & 0x0F;
+        A[13] = (block[21] >> 4) & 0x0F;
+        A[10] = block[22] & 0x0F;
+        A[11] = (block[22] >> 4) & 0x0F;
+        A[14] = block[23] & 0x0F;
+        A[15] = (block[23] >> 4) & 0x0F;
+    } else {
+        for (int i = 0; i < 16; i++) A[i] = 15;
+    }
+
+    int channels = has_alpha ? 4 : 3;
+
+    // iPF2: 4:2:2 - each horizontal pair shares chroma
+    // Row 0: pixels 0,1 share co[0]/cg[0], pixels 2,3 share co[1]/cg[1]
+    // Row 1: pixels 4,5 share co[2]/cg[2], pixels 6,7 share co[3]/cg[3]
+    // Row 2: pixels 8,9 share co[4]/cg[4], pixels 10,11 share co[5]/cg[5]
+    // Row 3: pixels 12,13 share co[6]/cg[6], pixels 14,15 share co[7]/cg[7]
+
+    int pixel_map[8][4] = {
+        {0, 1, 0, 1},    // co/cg index 0: pixels 0,1
+        {2, 3, 2, 3},    // co/cg index 1: pixels 2,3
+        {4, 5, 4, 5},    // co/cg index 2: pixels 4,5
+        {6, 7, 6, 7},    // co/cg index 3: pixels 6,7
+        {8, 9, 8, 9},    // co/cg index 4: pixels 8,9
+        {10, 11, 10, 11}, // co/cg index 5: pixels 10,11
+        {12, 13, 12, 13}, // co/cg index 6: pixels 12,13
+        {14, 15, 14, 15}  // co/cg index 7: pixels 14,15
+    };
+
+    for (int ci = 0; ci < 8; ci++) {
+        int p0 = pixel_map[ci][0];
+        int p1 = pixel_map[ci][1];
+
+        uint8_t quad[16];  // 4 pixels max (ycocg_to_rgb_quad writes 4 pixels)
+        ycocg_to_rgb_quad(co[ci], cg[ci], Y[p0], Y[p1], Y[p0], Y[p1],
+                          A[p0], A[p1], A[p0], A[p1], has_alpha, quad);
+
+        int row = p0 / 4;
+        int col0 = p0 % 4;
+        int col1 = p1 % 4;
+
+        memcpy(pixels + row * stride + col0 * channels, quad + 0 * channels, channels);
+        memcpy(pixels + row * stride + col1 * channels, quad + 1 * channels, channels);
+    }
+}
+
+// =============================================================================
+// Main Decoding
+// =============================================================================
+
+static int decode_ipf(const decoder_config_t *cfg) {
+    FILE *fp = fopen(cfg->input_file, "rb");
+    if (!fp) {
+        fprintf(stderr, "Error: Failed to open input file: %s\n", cfg->input_file);
+        return -1;
+    }
+
+    // Read header
+    ipf_header_t header;
+    if (read_ipf_header(fp, &header) < 0) {
+        fclose(fp);
+        return -1;
+    }
+
+    int has_alpha = (header.flags & IPF_FLAG_ALPHA) != 0;
+    int use_zstd = (header.flags & IPF_FLAG_ZSTD) != 0;
+    int progressive = (header.flags & IPF_FLAG_PROGRESSIVE) != 0;
+
+    if (cfg->verbose) {
+        printf("iPF Header:\n");
+        printf("  Size: %dx%d\n", header.width, header.height);
+        printf("  Type: iPF%d (%s)\n", header.type + 1,
+               header.type == 0 ? "4:2:0" : "4:2:2");
+        printf("  Flags: %s%s%s\n",
+               has_alpha ? "alpha " : "",
+               use_zstd ? "zstd " : "",
+               progressive ? "progressive " : "");
+        printf("  Uncompressed size: %u bytes\n", header.uncompressed_size);
+    }
+
+    if (progressive) {
+        fprintf(stderr, "Warning: Progressive mode not implemented, decoding as sequential\n");
+    }
+
+    // Read compressed/raw block data
+    fseek(fp, 0, SEEK_END);
+    long file_size = ftell(fp);
+    fseek(fp, IPF_HEADER_SIZE, SEEK_SET);
+
+    size_t compressed_size = file_size - IPF_HEADER_SIZE;
+    uint8_t *compressed_data = malloc(compressed_size);
+    if (!compressed_data) {
+        fclose(fp);
+        fprintf(stderr, "Error: Failed to allocate memory\n");
+        return -1;
+    }
+
+    if (fread(compressed_data, 1, compressed_size, fp) != compressed_size) {
+        free(compressed_data);
+        fclose(fp);
+        fprintf(stderr, "Error: Failed to read block data\n");
+        return -1;
+    }
+    fclose(fp);
+
+    // Decompress if needed
+    uint8_t *block_data;
+    size_t block_data_size;
+
+    if (use_zstd) {
+        block_data_size = header.uncompressed_size;
+        block_data = malloc(block_data_size);
+        if (!block_data) {
+            free(compressed_data);
+            fprintf(stderr, "Error: Failed to allocate decompression buffer\n");
+            return -1;
+        }
+
+        size_t result = ZSTD_decompress(block_data, block_data_size,
+                                        compressed_data, compressed_size);
+        if (ZSTD_isError(result)) {
+            fprintf(stderr, "Error: Zstd decompression failed: %s\n",
+                    ZSTD_getErrorName(result));
+            free(block_data);
+            free(compressed_data);
+            return -1;
+        }
+
+        if (cfg->verbose) {
+            printf("Decompressed: %zu -> %zu bytes\n", compressed_size, block_data_size);
+        }
+
+        free(compressed_data);
+    } else {
+        block_data = compressed_data;
+        block_data_size = compressed_size;
+    }
+
+    // Allocate output image
+    int channels = has_alpha ? 4 : 3;
+    size_t image_size = (size_t)header.width * header.height * channels;
+    uint8_t *image = malloc(image_size);
+    if (!image) {
+        free(block_data);
+        fprintf(stderr, "Error: Failed to allocate image buffer\n");
+        return -1;
+    }
+
+    // Decode blocks
+    int blocks_x = (header.width + 3) / 4;
+    int blocks_y = (header.height + 3) / 4;
+    int block_size = (header.type == IPF_TYPE_1) ? (has_alpha ? 20 : 12) : (has_alpha ? 24 : 16);
+    int row_stride = header.width * channels;
+    int block_stride = 4 * channels;  // 4 pixels per block row
+
+    size_t block_offset = 0;
+    for (int by = 0; by < blocks_y; by++) {
+        for (int bx = 0; bx < blocks_x; bx++) {
+            // Calculate output position
+            uint8_t *block_pixels = image + by * 4 * row_stride + bx * block_stride;
+
+            if (header.type == IPF_TYPE_1) {
+                decode_ipf1_block(block_data + block_offset, has_alpha, block_pixels, row_stride);
+            } else {
+                decode_ipf2_block(block_data + block_offset, has_alpha, block_pixels, row_stride);
+            }
+
+            block_offset += block_size;
+        }
+    }
+
+    free(block_data);
+
+    if (cfg->verbose) {
+        printf("Decoded %d blocks (%dx%d)\n", blocks_x * blocks_y, blocks_x, blocks_y);
+    }
+
+    // Output image
+    int result = 0;
+
+    if (cfg->raw_output) {
+        // Write raw RGB/RGBA data
+        FILE *out = fopen(cfg->output_file, "wb");
+        if (!out) {
+            fprintf(stderr, "Error: Failed to open output file: %s\n", cfg->output_file);
+            result = -1;
+        } else {
+            fwrite(image, 1, image_size, out);
+            fclose(out);
+            if (cfg->verbose) {
+                printf("Wrote %zu bytes raw %s data\n", image_size, has_alpha ? "RGBA" : "RGB24");
+            }
+        }
+    } else {
+        // Use FFmpeg to write output image
+        char cmd[MAX_PATH * 2];
+        const char *pix_fmt = has_alpha ? "rgba" : "rgb24";
+
+        snprintf(cmd, sizeof(cmd),
+                 "ffmpeg -hide_banner -v quiet -y -f rawvideo -pix_fmt %s -s %dx%d "
+                 "-i - \"%s\"",
+                 pix_fmt, header.width, header.height, cfg->output_file);
+
+        if (cfg->verbose) {
+            printf("FFmpeg command: %s\n", cmd);
+        }
+
+        FILE *pipe = popen(cmd, "w");
+        if (!pipe) {
+            fprintf(stderr, "Error: Failed to start FFmpeg\n");
+            result = -1;
+        } else {
+            fwrite(image, 1, image_size, pipe);
+            int status = pclose(pipe);
+            if (status != 0) {
+                fprintf(stderr, "Error: FFmpeg failed with status %d\n", status);
+                result = -1;
+            }
+        }
+    }
+
+    free(image);
+
+    return result;
+}
+
+// =============================================================================
+// Main Entry Point
+// =============================================================================
+
+int main(int argc, char *argv[]) {
+    decoder_config_t cfg = {
+        .input_file = NULL,
+        .output_file = NULL,
+        .verbose = 0,
+        .raw_output = 0
+    };
+
+    static struct option long_options[] = {
+        {"input",   required_argument, 0, 'i'},
+        {"output",  required_argument, 0, 'o'},
+        {"raw",     no_argument,       0, 'R'},
+        {"verbose", no_argument,       0, 'v'},
+        {"help",    no_argument,       0, 'h'},
+        {0, 0, 0, 0}
+    };
+
+    int opt;
+    while ((opt = getopt_long(argc, argv, "i:o:vh", long_options, NULL)) != -1) {
+        switch (opt) {
+            case 'i':
+                cfg.input_file = optarg;
+                break;
+            case 'o':
+                cfg.output_file = optarg;
+                break;
+            case 'R':
+                cfg.raw_output = 1;
+                break;
+            case 'v':
+                cfg.verbose = 1;
+                break;
+            case 'h':
+                print_usage(argv[0]);
+                return 0;
+            default:
+                print_usage(argv[0]);
+                return 1;
+        }
+    }
+
+    // Validate required arguments
+    if (!cfg.input_file || !cfg.output_file) {
+        fprintf(stderr, "Error: Input and output files are required\n\n");
+        print_usage(argv[0]);
+        return 1;
+    }
+
+    int result = decode_ipf(&cfg);
+
+    if (result == 0) {
+        printf("Successfully decoded: %s\n", cfg.output_file);
+    }
+
+    return result == 0 ? 0 : 1;
+}

ipf_encoder/encoder_ipf.c

@@ -0,0 +1,787 @@
+/**
+ * iPF Encoder - TSVM Interchangeable Picture Format Encoder
+ *
+ * Encodes images to iPF format (Type 1 or Type 2) with:
+ * - YCoCg colour space with chroma subsampling
+ * - 4x4 block encoding
+ * - Optional Zstd compression
+ * - Optional alpha channel
+ * - Optional Adam7 progressive ordering
+ *
+ * Created by CuriousTorvald and Claude on 2025-12-19.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include <math.h>
+#include <getopt.h>
+#include <zstd.h>
+
+// =============================================================================
+// Constants
+// =============================================================================
+
+#define IPF_MAGIC "\x1F\x54\x53\x56\x4D\x69\x50\x46"  // "\x1FTSVMiPF"
+#define IPF_HEADER_SIZE 28  // 8 magic + 2 width + 2 height + 1 flags + 1 type + 10 reserved + 4 uncompressed size
+
+#define DEFAULT_WIDTH 560
+#define DEFAULT_HEIGHT 448
+
+#define IPF_TYPE_1 0  // 4:2:0 chroma subsampling (12 bytes per block, +8 with alpha)
+#define IPF_TYPE_2 1  // 4:2:2 chroma subsampling (16 bytes per block, +8 with alpha)
+
+#define IPF_FLAG_ALPHA       0x01  // Has alpha channel
+#define IPF_FLAG_ZSTD        0x10  // Zstd compressed
+#define IPF_FLAG_PROGRESSIVE 0x80  // Adam7 progressive ordering
+
+#define MAX_PATH 4096
+
+// Bayer dithering kernel (4x4)
+static const float BAYER_4X4[16] = {
+     0.0f/16.0f,  8.0f/16.0f,  2.0f/16.0f, 10.0f/16.0f,
+    12.0f/16.0f,  4.0f/16.0f, 14.0f/16.0f,  6.0f/16.0f,
+     3.0f/16.0f, 11.0f/16.0f,  1.0f/16.0f,  9.0f/16.0f,
+    15.0f/16.0f,  7.0f/16.0f, 13.0f/16.0f,  5.0f/16.0f
+};
+
+// Adam7 interlace pattern - pass number (1-7) for each pixel in 8x8 block
+// 0 = not in this standard pattern, we'll adapt for 4x4 blocks
+static const int ADAM7_PASS[8][8] = {
+    {1, 6, 4, 6, 2, 6, 4, 6},
+    {7, 7, 7, 7, 7, 7, 7, 7},
+    {5, 6, 5, 6, 5, 6, 5, 6},
+    {7, 7, 7, 7, 7, 7, 7, 7},
+    {3, 6, 4, 6, 3, 6, 4, 6},
+    {7, 7, 7, 7, 7, 7, 7, 7},
+    {5, 6, 5, 6, 5, 6, 5, 6},
+    {7, 7, 7, 7, 7, 7, 7, 7}
+};
+
+// =============================================================================
+// Structures
+// =============================================================================
+
+typedef struct {
+    char *input_file;
+    char *output_file;
+    int width;
+    int height;
+    int ipf_type;        // 0 = iPF1, 1 = iPF2
+    int use_zstd;        // 1 = compress with Zstd
+    int force_alpha;     // 1 = force alpha channel in output
+    int no_alpha;        // 1 = strip alpha even if present in input
+    int progressive;     // 1 = Adam7 progressive ordering
+    int dither;          // Bayer dither pattern index (-1 = no dithering)
+    int verbose;
+} encoder_config_t;
+
+typedef struct {
+    uint8_t *data;       // RGB or RGBA data
+    int width;
+    int height;
+    int channels;        // 3 = RGB, 4 = RGBA
+    int has_alpha;       // 1 if input image has meaningful alpha
+} image_t;
+
+// =============================================================================
+// Utility Functions
+// =============================================================================
+
+static void print_usage(const char *program) {
+    printf("iPF Encoder - TSVM Interchangeable Picture Format\n");
+    printf("\nUsage: %s -i input.png -o output.ipf [options]\n\n", program);
+    printf("Required:\n");
+    printf("  -i, --input FILE         Input image file (any format FFmpeg supports)\n");
+    printf("  -o, --output FILE        Output iPF file\n");
+    printf("\nOptions:\n");
+    printf("  -s, --size WxH           Output size (default: %dx%d)\n", DEFAULT_WIDTH, DEFAULT_HEIGHT);
+    printf("  -t, --type N             iPF type: 1 (4:2:0, default) or 2 (4:2:2)\n");
+    printf("  --no-zstd                Disable Zstd compression (default: enabled)\n");
+    printf("  --alpha                  Force alpha channel in output\n");
+    printf("  --no-alpha               Strip alpha channel from input\n");
+    printf("  -p, --progressive        Use Adam7 progressive ordering\n");
+    printf("  -d, --dither N           Bayer dither pattern (0=4x4, -1=none, default: 0)\n");
+    printf("  -v, --verbose            Verbose output\n");
+    printf("  -h, --help               Show this help\n");
+    printf("\nExamples:\n");
+    printf("  %s -i photo.jpg -o photo.ipf\n", program);
+    printf("  %s -i logo.png -o logo.ipf --alpha\n", program);
+    printf("  %s -i image.png -o image.ipf -s 280x224 -t 2\n", program);
+}
+
+static int clampi(int v, int lo, int hi) {
+    return v < lo ? lo : (v > hi ? hi : v);
+}
+
+// Convert chroma value [-1..1] to 4-bit [0..15]
+static int chroma_to_four_bits(float f) {
+    return clampi((int)roundf(f * 8.0f) + 7, 0, 15);
+}
+
+// =============================================================================
+// Image Loading via FFmpeg
+// =============================================================================
+
+/**
+ * Probe input image dimensions using FFmpeg.
+ * Returns 0 on success, -1 on error.
+ */
+static int probe_image_dimensions(const char *input_file, int *width, int *height, int *has_alpha) {
+    char cmd[MAX_PATH * 2];
+
+    // Use ffprobe to get dimensions and pixel format
+    snprintf(cmd, sizeof(cmd),
+             "ffprobe -v quiet -select_streams v:0 -show_entries stream=width,height,pix_fmt "
+             "-of csv=p=0:s=x \"%s\" 2>/dev/null",
+             input_file);
+
+    FILE *fp = popen(cmd, "r");
+    if (!fp) {
+        fprintf(stderr, "Error: Failed to run ffprobe\n");
+        return -1;
+    }
+
+    char buffer[256];
+    if (fgets(buffer, sizeof(buffer), fp) == NULL) {
+        pclose(fp);
+        fprintf(stderr, "Error: Failed to read image info\n");
+        return -1;
+    }
+    pclose(fp);
+
+    // Parse "width x height x pix_fmt"
+    char pix_fmt[64] = "";
+    if (sscanf(buffer, "%dx%dx%63s", width, height, pix_fmt) < 2) {
+        // Try alternate format without pix_fmt
+        if (sscanf(buffer, "%dx%d", width, height) != 2) {
+            fprintf(stderr, "Error: Failed to parse image dimensions\n");
+            return -1;
+        }
+    }
+
+    // Check if pixel format indicates alpha
+    *has_alpha = (strstr(pix_fmt, "rgba") != NULL ||
+                  strstr(pix_fmt, "argb") != NULL ||
+                  strstr(pix_fmt, "bgra") != NULL ||
+                  strstr(pix_fmt, "abgr") != NULL ||
+                  strstr(pix_fmt, "ya") != NULL ||
+                  strstr(pix_fmt, "pal8") != NULL ||  // palette may have alpha
+                  strstr(pix_fmt, "yuva") != NULL);
+
+    return 0;
+}
+
+/**
+ * Load and resize image using FFmpeg.
+ * Maintains aspect ratio and crops to target size.
+ * Returns image data or NULL on error.
+ */
+static image_t* load_image(const char *input_file, int target_width, int target_height,
+                           int want_alpha, int verbose) {
+    int src_width, src_height, src_has_alpha;
+
+    // Probe source dimensions
+    if (probe_image_dimensions(input_file, &src_width, &src_height, &src_has_alpha) < 0) {
+        return NULL;
+    }
+
+    if (verbose) {
+        printf("Source image: %dx%d, alpha: %s\n",
+               src_width, src_height, src_has_alpha ? "yes" : "no");
+    }
+
+    // Determine if we need alpha channel
+    int use_alpha = want_alpha || src_has_alpha;
+    int channels = use_alpha ? 4 : 3;
+    const char *pix_fmt = use_alpha ? "rgba" : "rgb24";
+
+    // Build FFmpeg command with scale and crop filter
+    char cmd[MAX_PATH * 2];
+    snprintf(cmd, sizeof(cmd),
+             "ffmpeg -hide_banner -v quiet -i \"%s\" -f rawvideo -pix_fmt %s -vf "
+             "\"scale=%d:%d:force_original_aspect_ratio=increase,crop=%d:%d\" -frames:v 1 -",
+             input_file, pix_fmt, target_width, target_height, target_width, target_height);
+
+    if (verbose) {
+        printf("FFmpeg command: %s\n", cmd);
+    }
+
+    FILE *fp = popen(cmd, "r");
+    if (!fp) {
+        fprintf(stderr, "Error: Failed to start FFmpeg\n");
+        return NULL;
+    }
+
+    // Allocate image
+    image_t *img = malloc(sizeof(image_t));
+    if (!img) {
+        pclose(fp);
+        return NULL;
+    }
+
+    size_t data_size = (size_t)target_width * target_height * channels;
+    img->data = malloc(data_size);
+    if (!img->data) {
+        free(img);
+        pclose(fp);
+        return NULL;
+    }
+
+    img->width = target_width;
+    img->height = target_height;
+    img->channels = channels;
+    img->has_alpha = use_alpha;
+
+    // Read image data
+    size_t bytes_read = fread(img->data, 1, data_size, fp);
+    pclose(fp);
+
+    if (bytes_read != data_size) {
+        fprintf(stderr, "Error: Expected %zu bytes, got %zu\n", data_size, bytes_read);
+        free(img->data);
+        free(img);
+        return NULL;
+    }
+
+    if (verbose) {
+        printf("Loaded %dx%d image, %d channels, %zu bytes\n",
+               img->width, img->height, img->channels, data_size);
+    }
+
+    return img;
+}
+
+static void free_image(image_t *img) {
+    if (img) {
+        free(img->data);
+        free(img);
+    }
+}
+
+// =============================================================================
+// iPF Block Encoding
+// =============================================================================
+
+/**
+ * Encode a 4x4 block to YCoCg with dithering.
+ * Returns arrays of Y (16 values), A (16 values), Co (16 values), Cg (16 values).
+ */
+static void encode_block_to_ycocg(const image_t *img, int block_x, int block_y,
+                                  int dither_pattern,
+                                  int *Y_out, int *A_out, float *Co_out, float *Cg_out) {
+    for (int py = 0; py < 4; py++) {
+        for (int px = 0; px < 4; px++) {
+            int ox = block_x * 4 + px;
+            int oy = block_y * 4 + py;
+
+            // Handle out-of-bounds (extend edge pixels)
+            ox = clampi(ox, 0, img->width - 1);
+            oy = clampi(oy, 0, img->height - 1);
+
+            // Get dither threshold
+            float t = 0.0f;
+            if (dither_pattern >= 0) {
+                t = BAYER_4X4[(py % 4) * 4 + (px % 4)];
+            }
+
+            // Read pixel
+            int offset = (oy * img->width + ox) * img->channels;
+            float r0 = img->data[offset + 0] / 255.0f;
+            float g0 = (img->channels >= 3) ? img->data[offset + 1] / 255.0f : r0;
+            float b0 = (img->channels >= 3) ? img->data[offset + 2] / 255.0f : r0;
+            float a0 = (img->channels == 4) ? img->data[offset + 3] / 255.0f : 1.0f;
+
+            // Apply dithering
+            float r = floorf((t / 15.0f + r0) * 15.0f) / 15.0f;
+            float g = floorf((t / 15.0f + g0) * 15.0f) / 15.0f;
+            float b = floorf((t / 15.0f + b0) * 15.0f) / 15.0f;
+            float a = floorf((t / 15.0f + a0) * 15.0f) / 15.0f;
+
+            // Convert to YCoCg
+            float co = r - b;           // [-1..1]
+            float tmp = b + co / 2.0f;
+            float cg = g - tmp;         // [-1..1]
+            float y = tmp + cg / 2.0f;  // [0..1]
+
+            int index = py * 4 + px;
+            Y_out[index] = (int)roundf(y * 15.0f);
+            A_out[index] = (int)roundf(a * 15.0f);
+            Co_out[index] = co;
+            Cg_out[index] = cg;
+        }
+    }
+}
+
+/**
+ * Encode iPF1 block (4:2:0 chroma subsampling).
+ * Returns 12 bytes (or 20 with alpha).
+ */
+static int encode_ipf1_block(const int *Ys, const int *As, const float *COs, const float *CGs,
+                             int has_alpha, uint8_t *out) {
+    // Subsample Co/Cg by averaging 2x2 regions (4:2:0)
+    int cos1 = chroma_to_four_bits((COs[0] + COs[1] + COs[4] + COs[5]) / 4.0f);
+    int cos2 = chroma_to_four_bits((COs[2] + COs[3] + COs[6] + COs[7]) / 4.0f);
+    int cos3 = chroma_to_four_bits((COs[8] + COs[9] + COs[12] + COs[13]) / 4.0f);
+    int cos4 = chroma_to_four_bits((COs[10] + COs[11] + COs[14] + COs[15]) / 4.0f);
+
+    int cgs1 = chroma_to_four_bits((CGs[0] + CGs[1] + CGs[4] + CGs[5]) / 4.0f);
+    int cgs2 = chroma_to_four_bits((CGs[2] + CGs[3] + CGs[6] + CGs[7]) / 4.0f);
+    int cgs3 = chroma_to_four_bits((CGs[8] + CGs[9] + CGs[12] + CGs[13]) / 4.0f);
+    int cgs4 = chroma_to_four_bits((CGs[10] + CGs[11] + CGs[14] + CGs[15]) / 4.0f);
+
+    // Pack according to iPF1 format
+    // uint16 [Co4 | Co3 | Co2 | Co1]
+    out[0] = (cos2 << 4) | cos1;
+    out[1] = (cos4 << 4) | cos3;
+    // uint16 [Cg4 | Cg3 | Cg2 | Cg1]
+    out[2] = (cgs2 << 4) | cgs1;
+    out[3] = (cgs4 << 4) | cgs3;
+    // Y values: [Y1|Y0|Y5|Y4], [Y3|Y2|Y7|Y6], [Y9|Y8|YD|YC], [YB|YA|YF|YE]
+    out[4] = (Ys[1] << 4) | Ys[0];
+    out[5] = (Ys[5] << 4) | Ys[4];
+    out[6] = (Ys[3] << 4) | Ys[2];
+    out[7] = (Ys[7] << 4) | Ys[6];
+    out[8] = (Ys[9] << 4) | Ys[8];
+    out[9] = (Ys[13] << 4) | Ys[12];
+    out[10] = (Ys[11] << 4) | Ys[10];
+    out[11] = (Ys[15] << 4) | Ys[14];
+
+    int block_size = 12;
+
+    if (has_alpha) {
+        // Alpha values: same layout as Y
+        out[12] = (As[1] << 4) | As[0];
+        out[13] = (As[5] << 4) | As[4];
+        out[14] = (As[3] << 4) | As[2];
+        out[15] = (As[7] << 4) | As[6];
+        out[16] = (As[9] << 4) | As[8];
+        out[17] = (As[13] << 4) | As[12];
+        out[18] = (As[11] << 4) | As[10];
+        out[19] = (As[15] << 4) | As[14];
+        block_size = 20;
+    }
+
+    return block_size;
+}
+
+/**
+ * Encode iPF2 block (4:2:2 chroma subsampling).
+ * Returns 16 bytes (or 24 with alpha).
+ */
+static int encode_ipf2_block(const int *Ys, const int *As, const float *COs, const float *CGs,
+                             int has_alpha, uint8_t *out) {
+    // Subsample Co/Cg horizontally only (4:2:2) - 8 values each
+    int cos1 = chroma_to_four_bits((COs[0] + COs[1]) / 2.0f);
+    int cos2 = chroma_to_four_bits((COs[2] + COs[3]) / 2.0f);
+    int cos3 = chroma_to_four_bits((COs[4] + COs[5]) / 2.0f);
+    int cos4 = chroma_to_four_bits((COs[6] + COs[7]) / 2.0f);
+    int cos5 = chroma_to_four_bits((COs[8] + COs[9]) / 2.0f);
+    int cos6 = chroma_to_four_bits((COs[10] + COs[11]) / 2.0f);
+    int cos7 = chroma_to_four_bits((COs[12] + COs[13]) / 2.0f);
+    int cos8 = chroma_to_four_bits((COs[14] + COs[15]) / 2.0f);
+
+    int cgs1 = chroma_to_four_bits((CGs[0] + CGs[1]) / 2.0f);
+    int cgs2 = chroma_to_four_bits((CGs[2] + CGs[3]) / 2.0f);
+    int cgs3 = chroma_to_four_bits((CGs[4] + CGs[5]) / 2.0f);
+    int cgs4 = chroma_to_four_bits((CGs[6] + CGs[7]) / 2.0f);
+    int cgs5 = chroma_to_four_bits((CGs[8] + CGs[9]) / 2.0f);
+    int cgs6 = chroma_to_four_bits((CGs[10] + CGs[11]) / 2.0f);
+    int cgs7 = chroma_to_four_bits((CGs[12] + CGs[13]) / 2.0f);
+    int cgs8 = chroma_to_four_bits((CGs[14] + CGs[15]) / 2.0f);
+
+    // Pack according to iPF2 format
+    // uint32 [Co8 | Co7 | Co6 | Co5 | Co4 | Co3 | Co2 | Co1]
+    out[0] = (cos2 << 4) | cos1;
+    out[1] = (cos4 << 4) | cos3;
+    out[2] = (cos6 << 4) | cos5;
+    out[3] = (cos8 << 4) | cos7;
+    // uint32 [Cg8 | Cg7 | Cg6 | Cg5 | Cg4 | Cg3 | Cg2 | Cg1]
+    out[4] = (cgs2 << 4) | cgs1;
+    out[5] = (cgs4 << 4) | cgs3;
+    out[6] = (cgs6 << 4) | cgs5;
+    out[7] = (cgs8 << 4) | cgs7;
+    // Y values: same as iPF1
+    out[8] = (Ys[1] << 4) | Ys[0];
+    out[9] = (Ys[5] << 4) | Ys[4];
+    out[10] = (Ys[3] << 4) | Ys[2];
+    out[11] = (Ys[7] << 4) | Ys[6];
+    out[12] = (Ys[9] << 4) | Ys[8];
+    out[13] = (Ys[13] << 4) | Ys[12];
+    out[14] = (Ys[11] << 4) | Ys[10];
+    out[15] = (Ys[15] << 4) | Ys[14];
+
+    int block_size = 16;
+
+    if (has_alpha) {
+        // Alpha values: same layout as Y
+        out[16] = (As[1] << 4) | As[0];
+        out[17] = (As[5] << 4) | As[4];
+        out[18] = (As[3] << 4) | As[2];
+        out[19] = (As[7] << 4) | As[6];
+        out[20] = (As[9] << 4) | As[8];
+        out[21] = (As[13] << 4) | As[12];
+        out[22] = (As[11] << 4) | As[10];
+        out[23] = (As[15] << 4) | As[14];
+        block_size = 24;
+    }
+
+    return block_size;
+}
+
+// =============================================================================
+// Adam7 Progressive Ordering
+// =============================================================================
+
+/**
+ * Get Adam7 pass number for a block at (block_x, block_y).
+ * For blocks, we use a simplified version based on block position.
+ */
+static int get_adam7_pass(int block_x, int block_y) {
+    // Use Adam7 pattern for 8x8 blocks, but adapt for 4x4 block indices
+    int px = (block_x * 4) % 8;
+    int py = (block_y * 4) % 8;
+    return ADAM7_PASS[py][px];
+}
+
+/**
+ * Encode blocks in Adam7 progressive order.
+ * Returns the encoded block data in progressive order.
+ */
+static uint8_t* encode_progressive(const image_t *img, const encoder_config_t *cfg,
+                                   int has_alpha, size_t *out_size) {
+    int blocks_x = (img->width + 3) / 4;
+    int blocks_y = (img->height + 3) / 4;
+    int total_blocks = blocks_x * blocks_y;
+
+    int block_size = (cfg->ipf_type == IPF_TYPE_1) ? (has_alpha ? 20 : 12) : (has_alpha ? 24 : 16);
+    size_t max_size = (size_t)total_blocks * block_size;
+
+    uint8_t *output = malloc(max_size);
+    if (!output) return NULL;
+
+    // Temporary storage for all encoded blocks
+    uint8_t *all_blocks = malloc(max_size);
+    if (!all_blocks) {
+        free(output);
+        return NULL;
+    }
+
+    // Encode all blocks first
+    size_t offset = 0;
+    for (int by = 0; by < blocks_y; by++) {
+        for (int bx = 0; bx < blocks_x; bx++) {
+            int Ys[16], As[16];
+            float COs[16], CGs[16];
+
+            encode_block_to_ycocg(img, bx, by, cfg->dither, Ys, As, COs, CGs);
+
+            if (cfg->ipf_type == IPF_TYPE_1) {
+                encode_ipf1_block(Ys, As, COs, CGs, has_alpha, all_blocks + offset);
+            } else {
+                encode_ipf2_block(Ys, As, COs, CGs, has_alpha, all_blocks + offset);
+            }
+            offset += block_size;
+        }
+    }
+
+    // Reorder blocks according to Adam7 progressive order (7 passes)
+    size_t out_offset = 0;
+    for (int pass = 1; pass <= 7; pass++) {
+        for (int by = 0; by < blocks_y; by++) {
+            for (int bx = 0; bx < blocks_x; bx++) {
+                if (get_adam7_pass(bx, by) == pass) {
+                    int block_idx = by * blocks_x + bx;
+                    memcpy(output + out_offset, all_blocks + block_idx * block_size, block_size);
+                    out_offset += block_size;
+                }
+            }
+        }
+    }
+
+    free(all_blocks);
+    *out_size = out_offset;
+    return output;
+}
+
+/**
+ * Encode blocks in sequential (raster) order.
+ */
+static uint8_t* encode_sequential(const image_t *img, const encoder_config_t *cfg,
+                                  int has_alpha, size_t *out_size) {
+    int blocks_x = (img->width + 3) / 4;
+    int blocks_y = (img->height + 3) / 4;
+    int total_blocks = blocks_x * blocks_y;
+
+    int block_size = (cfg->ipf_type == IPF_TYPE_1) ? (has_alpha ? 20 : 12) : (has_alpha ? 24 : 16);
+    size_t max_size = (size_t)total_blocks * block_size;
+
+    uint8_t *output = malloc(max_size);
+    if (!output) return NULL;
+
+    size_t offset = 0;
+    for (int by = 0; by < blocks_y; by++) {
+        for (int bx = 0; bx < blocks_x; bx++) {
+            int Ys[16], As[16];
+            float COs[16], CGs[16];
+
+            encode_block_to_ycocg(img, bx, by, cfg->dither, Ys, As, COs, CGs);
+
+            if (cfg->ipf_type == IPF_TYPE_1) {
+                offset += encode_ipf1_block(Ys, As, COs, CGs, has_alpha, output + offset);
+            } else {
+                offset += encode_ipf2_block(Ys, As, COs, CGs, has_alpha, output + offset);
+            }
+        }
+    }
+
+    *out_size = offset;
+    return output;
+}
+
+// =============================================================================
+// iPF File Writing
+// =============================================================================
+
+static int write_ipf_file(const char *output_file, const encoder_config_t *cfg,
+                          const image_t *img, int verbose) {
+    // Determine if we use alpha
+    int has_alpha = 0;
+    if (cfg->force_alpha) {
+        has_alpha = 1;
+    } else if (!cfg->no_alpha && img->has_alpha) {
+        has_alpha = 1;
+    }
+
+    // Encode blocks
+    size_t block_data_size;
+    uint8_t *block_data;
+
+    if (cfg->progressive) {
+        block_data = encode_progressive(img, cfg, has_alpha, &block_data_size);
+    } else {
+        block_data = encode_sequential(img, cfg, has_alpha, &block_data_size);
+    }
+
+    if (!block_data) {
+        fprintf(stderr, "Error: Failed to encode image blocks\n");
+        return -1;
+    }
+
+    if (verbose) {
+        printf("Encoded %zu bytes of block data\n", block_data_size);
+    }
+
+    // Prepare output data (may be compressed)
+    uint8_t *output_data = block_data;
+    size_t output_size = block_data_size;
+    uint8_t *compressed_data = NULL;
+
+    if (cfg->use_zstd) {
+        size_t max_compressed = ZSTD_compressBound(block_data_size);
+        compressed_data = malloc(max_compressed);
+        if (!compressed_data) {
+            free(block_data);
+            fprintf(stderr, "Error: Failed to allocate compression buffer\n");
+            return -1;
+        }
+
+        output_size = ZSTD_compress(compressed_data, max_compressed,
+                                    block_data, block_data_size, 7);
+        if (ZSTD_isError(output_size)) {
+            fprintf(stderr, "Error: Zstd compression failed: %s\n",
+                    ZSTD_getErrorName(output_size));
+            free(block_data);
+            free(compressed_data);
+            return -1;
+        }
+
+        output_data = compressed_data;
+
+        if (verbose) {
+            printf("Compressed: %zu -> %zu bytes (%.1f%%)\n",
+                   block_data_size, output_size,
+                   100.0 * output_size / block_data_size);
+        }
+    }
+
+    // Open output file
+    FILE *fp = fopen(output_file, "wb");
+    if (!fp) {
+        fprintf(stderr, "Error: Failed to open output file: %s\n", output_file);
+        free(block_data);
+        if (compressed_data) free(compressed_data);
+        return -1;
+    }
+
+    // Build flags byte
+    uint8_t flags = 0;
+    if (has_alpha) flags |= IPF_FLAG_ALPHA;
+    if (cfg->use_zstd) flags |= IPF_FLAG_ZSTD;
+    if (cfg->progressive) flags |= IPF_FLAG_PROGRESSIVE | IPF_FLAG_ZSTD;  // Progressive always sets zstd flag
+
+    // Write header
+    // Magic: "\x1FTSVMiPF" (8 bytes)
+    fwrite(IPF_MAGIC, 1, 8, fp);
+
+    // Width (uint16 LE)
+    uint16_t width_le = (uint16_t)cfg->width;
+    fwrite(&width_le, 2, 1, fp);
+
+    // Height (uint16 LE)
+    uint16_t height_le = (uint16_t)cfg->height;
+    fwrite(&height_le, 2, 1, fp);
+
+    // Flags (uint8)
+    fwrite(&flags, 1, 1, fp);
+
+    // Type (uint8)
+    uint8_t type_byte = (uint8_t)cfg->ipf_type;
+    fwrite(&type_byte, 1, 1, fp);
+
+    // Reserved (10 bytes)
+    uint8_t reserved[10] = {0};
+    fwrite(reserved, 1, 10, fp);
+
+    // Uncompressed size (uint32 LE)
+    uint32_t uncompressed_size_le = (uint32_t)block_data_size;
+    fwrite(&uncompressed_size_le, 4, 1, fp);
+
+    // Write block data
+    fwrite(output_data, 1, output_size, fp);
+
+    fclose(fp);
+
+    if (verbose) {
+        printf("Wrote %zu bytes to %s\n", IPF_HEADER_SIZE + output_size, output_file);
+        printf("  Format: iPF%d, %dx%d\n", cfg->ipf_type + 1, cfg->width, cfg->height);
+        printf("  Flags: %s%s%s\n",
+               has_alpha ? "alpha " : "",
+               cfg->use_zstd ? "zstd " : "",
+               cfg->progressive ? "progressive " : "");
+    }
+
+    free(block_data);
+    if (compressed_data) free(compressed_data);
+
+    return 0;
+}
+
+// =============================================================================
+// Main Entry Point
+// =============================================================================
+
+static int parse_size(const char *arg, int *width, int *height) {
+    return sscanf(arg, "%dx%d", width, height) == 2 ? 0 : -1;
+}
+
+int main(int argc, char *argv[]) {
+    encoder_config_t cfg = {
+        .input_file = NULL,
+        .output_file = NULL,
+        .width = DEFAULT_WIDTH,
+        .height = DEFAULT_HEIGHT,
+        .ipf_type = IPF_TYPE_1,
+        .use_zstd = 1,
+        .force_alpha = 0,
+        .no_alpha = 0,
+        .progressive = 0,
+        .dither = 0,
+        .verbose = 0
+    };
+
+    static struct option long_options[] = {
+        {"input",       required_argument, 0, 'i'},
+        {"output",      required_argument, 0, 'o'},
+        {"size",        required_argument, 0, 's'},
+        {"type",        required_argument, 0, 't'},
+        {"no-zstd",     no_argument,       0, 'Z'},
+        {"alpha",       no_argument,       0, 'A'},
+        {"no-alpha",    no_argument,       0, 'N'},
+        {"progressive", no_argument,       0, 'p'},
+        {"dither",      required_argument, 0, 'd'},
+        {"verbose",     no_argument,       0, 'v'},
+        {"help",        no_argument,       0, 'h'},
+        {0, 0, 0, 0}
+    };
+
+    int opt;
+    while ((opt = getopt_long(argc, argv, "i:o:s:t:pd:vh", long_options, NULL)) != -1) {
+        switch (opt) {
+            case 'i':
+                cfg.input_file = optarg;
+                break;
+            case 'o':
+                cfg.output_file = optarg;
+                break;
+            case 's':
+                if (parse_size(optarg, &cfg.width, &cfg.height) != 0) {
+                    fprintf(stderr, "Error: Invalid size format (use WxH)\n");
+                    return 1;
+                }
+                break;
+            case 't':
+                cfg.ipf_type = atoi(optarg) - 1;  // User specifies 1 or 2
+                if (cfg.ipf_type < 0 || cfg.ipf_type > 1) {
+                    fprintf(stderr, "Error: Invalid iPF type (use 1 or 2)\n");
+                    return 1;
+                }
+                break;
+            case 'Z':
+                cfg.use_zstd = 0;
+                break;
+            case 'A':
+                cfg.force_alpha = 1;
+                break;
+            case 'N':
+                cfg.no_alpha = 1;
+                break;
+            case 'p':
+                cfg.progressive = 1;
+                break;
+            case 'd':
+                cfg.dither = atoi(optarg);
+                break;
+            case 'v':
+                cfg.verbose = 1;
+                break;
+            case 'h':
+                print_usage(argv[0]);
+                return 0;
+            default:
+                print_usage(argv[0]);
+                return 1;
+        }
+    }
+
+    // Validate required arguments
+    if (!cfg.input_file || !cfg.output_file) {
+        fprintf(stderr, "Error: Input and output files are required\n\n");
+        print_usage(argv[0]);
+        return 1;
+    }
+
+    // Load image
+    if (cfg.verbose) {
+        printf("Loading image: %s\n", cfg.input_file);
+    }
+
+    image_t *img = load_image(cfg.input_file, cfg.width, cfg.height,
+                              cfg.force_alpha, cfg.verbose);
+    if (!img) {
+        fprintf(stderr, "Error: Failed to load image\n");
+        return 1;
+    }
+
+    // Encode and write iPF file
+    int result = write_ipf_file(cfg.output_file, &cfg, img, cfg.verbose);
+
+    free_image(img);
+
+    if (result == 0) {
+        printf("Successfully encoded: %s\n", cfg.output_file);
+    }
+
+    return result == 0 ? 0 : 1;
+}

lib/_create_graaljs_edit.md

@@ -1,20 +1,8 @@
-## How To Edit the Graaljs Jars
+## GraalJS JAR Editing (OBSOLETE)
 
-0. Download following from Maven:
+The META-INF/services cross-registration hack was needed for GraalJS 22.3.1 where
+`js` and `regex` JARs each needed the other's `TruffleLanguage$Provider` registered.
 
-    org.graalvm.js:js:00.0.0
-    org.graalvm.js:js-scriptengine:00.0.0
-
-1. grab `js-00.0.0.jar`
-2. on `META-INF/services/com.oracle.truffle.api.TruffleLanguage$Provider`, edit as shown:
-
-    com.oracle.truffle.js.lang.JavaScriptLanguageProvider (existing line)
-    com.oracle.truffle.regex.RegexLanguageProvider        (<< add this line)
-
-3. grab `regex-00.0.0.jar`
-4. on `META-INF/services/com.oracle.truffle.api.TruffleLanguage$Provider`, edit as shown:
-
-    com.oracle.truffle.regex.RegexLanguageProvider        (existing line)
-    com.oracle.truffle.js.lang.JavaScriptLanguageProvider (<< add this line)
-
-5. Re-zip two files
+As of GraalJS 24.1.2, the service discovery mechanism changed to
+`TruffleLanguageProvider` and each JAR registers its own provider independently.
+No JAR editing is required.