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taud: amiga mode pitchbend

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minjaesong
2026-04-29 20:07:25 +09:00
parent 1148454fb3
commit b838b35525
9 changed files with 174 additions and 72 deletions
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47
tsvm_core/src/net/torvald/tsvm/peripheral/AudioAdapter.kt
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@@ -13,6 +13,7 @@ import net.torvald.tsvm.VM
import net.torvald.tsvm.toInt
import java.io.ByteArrayInputStream
import kotlin.math.cos
import kotlin.math.log2
import kotlin.math.pow
import kotlin.math.roundToInt
import kotlin.math.sin
@@ -124,6 +125,12 @@ class AudioAdapter(val vm: VM) : PeriBase(VM.PERITYPE_SOUND) {
const val SAMPLING_RATE = 32000
const val TRACKER_CHUNK = 512
const val TRACKER_C3 = 0x4000
// Amiga period at TRACKER_C3 for a standard 8363 Hz instrument (NTSC clock 3579545 Hz).
// Used to implement Amiga-mode pitch slides (effect '1' f-bit or song-table flag).
const val AMIGA_BASE_PERIOD = 214.0
// Scale factor that converts a Taud coarse-slide unit back to one Amiga period unit.
// Taud coarse unit = round(ST3_unit × 64/3), so the inverse is × 3/64.
const val AMIGA_PERIOD_SCALE = 3.0 / 64.0
}
internal val sampleBin = UnsafeHelper.allocate(770048L, this)
@@ -1165,6 +1172,16 @@ class AudioAdapter(val vm: VM) : PeriBase(VM.PERITYPE_SOUND) {
private fun computePlaybackRate(inst: TaudInst, noteVal: Int): Double =
inst.samplingRate.toDouble() / SAMPLING_RATE * 2.0.pow((noteVal - TRACKER_C3) / 4096.0)
// Applies one tick of Amiga-mode pitch slide. slideArg uses the same sign convention as
// linear mode: negative = pitch down (E effect), positive = pitch up (F effect).
// The Taud coarse-slide value is converted back to Amiga period units via AMIGA_PERIOD_SCALE.
private fun amigaSlide(noteVal: Int, slideArg: Int): Int {
val period = AMIGA_BASE_PERIOD * 2.0.pow(-(noteVal - TRACKER_C3).toDouble() / 4096.0)
// Negate slideArg: pitch down (slideArg < 0) → period up, pitch up (slideArg > 0) → period down.
val newPeriod = (period - slideArg * AMIGA_PERIOD_SCALE).coerceAtLeast(1.0)
return (TRACKER_C3 + 4096.0 * log2(AMIGA_BASE_PERIOD / newPeriod)).roundToInt()
}
private fun advanceEnvelope(voice: Voice, inst: TaudInst, tickSec: Double) {
// Volume envelope
// sustain byte: bit7=enabled, bits[5:3]=end_idx, bits[2:0]=start_idx
@@ -1406,8 +1423,12 @@ class AudioAdapter(val vm: VM) : PeriBase(VM.PERITYPE_SOUND) {
when (op) {
EffectOp.OP_NONE -> {}
EffectOp.OP_1 -> {
// 1 $01xx — Set stereo panning law. High byte selects subcommand; only $01 is defined.
if ((rawArg ushr 8) == 0x01) ts.panLaw = rawArg and 0xFF
// 1 $xx00 — Global behaviour flags byte in the high byte (see TAUD_NOTE_EFFECTS.md §1).
// bit 0 (p): 0=linear pan, 1=equal-power pan
// bit 1 (f): 0=linear pitch slides, 1=Amiga-mode pitch slides
val flags = rawArg ushr 8
ts.panLaw = flags and 1
ts.amigaMode = (flags and 2) != 0
}
EffectOp.OP_A -> {
val tr = (rawArg ushr 8) and 0xFF
@@ -1609,7 +1630,10 @@ class AudioAdapter(val vm: VM) : PeriBase(VM.PERITYPE_SOUND) {
// Pitch slides (E/F coarse on tick > 0).
if (ts.tickInRow > 0 && (voice.slideMode == 1 || voice.slideMode == 2)) {
voice.noteVal = (voice.noteVal + voice.slideArg).coerceIn(0, 0xFFFE)
voice.noteVal = if (ts.amigaMode)
amigaSlide(voice.noteVal, voice.slideArg).coerceIn(0, 0xFFFE)
else
(voice.noteVal + voice.slideArg).coerceIn(0, 0xFFFE)
voice.basePitch = voice.noteVal
}
@@ -2071,7 +2095,8 @@ class AudioAdapter(val vm: VM) : PeriBase(VM.PERITYPE_SOUND) {
val voices = Array(20) { Voice() }
// Global mixer config (effect 1).
var panLaw = 0 // 0 = linear balance (default), 1 = equal-power
var panLaw = 0 // 0 = linear balance (default), 1 = equal-power
var amigaMode = false // false = linear pitch slides, true = Amiga period-space slides
// Pending row-end events (set during a row by B/C; consumed at row end).
var pendingOrderJump = -1 // -1 = none; otherwise the order index to jump to
@@ -2111,6 +2136,10 @@ class AudioAdapter(val vm: VM) : PeriBase(VM.PERITYPE_SOUND) {
) {
var trackerState: TrackerState? = TrackerState() // default mode is tracker (isPcmMode=false)
// Initial global behaviour flags (song-table byte, written via MMIO register 7 in tracker mode).
// Applied to TrackerState on every resetParams(); in-pattern effect '1' can override later.
var initialGlobalFlags: Int = 0
// flags
var isPcmMode: Boolean = false
set(value) {
@@ -2140,7 +2169,7 @@ class AudioAdapter(val vm: VM) : PeriBase(VM.PERITYPE_SOUND) {
4 -> masterVolume.toByte()
5 -> masterPan.toByte()
6 -> (isPcmMode.toInt(7) or isPlaying.toInt(4) or pcmQueueSizeIndex.and(15)).toByte()
7 -> 0
7 -> initialGlobalFlags.toByte()
8 -> (bpm - 24).toByte()
9 -> tickRate.toByte()
else -> throw InternalError("Bad offset $index")
@@ -2165,7 +2194,10 @@ class AudioAdapter(val vm: VM) : PeriBase(VM.PERITYPE_SOUND) {
pcmQueueSizeIndex = (it and 0b00001111)
if (it and 0b00100000 != 0) purgeQueue()
} }
7 -> if (isPcmMode) { pcmUpload = true } else {}
7 -> if (isPcmMode) { pcmUpload = true } else {
initialGlobalFlags = byte
trackerState?.let { ts -> ts.panLaw = byte and 1; ts.amigaMode = (byte and 2) != 0 }
}
8 -> { bpm = byte + 24 }
9 -> { tickRate = byte }
else -> throw InternalError("Bad offset $index")
@@ -2194,7 +2226,8 @@ class AudioAdapter(val vm: VM) : PeriBase(VM.PERITYPE_SOUND) {
ts.pendingOrderJump = -1; ts.pendingRowJump = -1
ts.patternDelayRemaining = 0; ts.patternDelayActive = false
ts.sexWinningChannel = -1
ts.panLaw = 0
ts.panLaw = initialGlobalFlags and 1
ts.amigaMode = (initialGlobalFlags and 2) != 0
ts.voices.forEach {
it.active = false
it.channelVolume = 0x3F