preemption proof-of-concept

tsvm_core/src/net/torvald/tsvm/VM.kt

@@ -1,5 +1,6 @@
 package net.torvald.tsvm
 
+import kotlinx.coroutines.Job
 import net.torvald.UnsafeHelper
 import net.torvald.UnsafePtr
 import net.torvald.tsvm.peripheral.IOSpace
@@ -19,6 +20,7 @@ class ErrorIllegalAccess(vm: VM, addr: Long) : RuntimeException("Segmentation fa
  */
 
 class VM(
+    val assetsDir: String,
     _memsize: Long,
     val worldInterface: WorldInterface,
     val roms: Array<VMProgramRom?> // first ROM must contain the BIOS
@@ -26,8 +28,10 @@ class VM(
 
     val id = java.util.Random().nextInt()
 
+    internal val contexts = ArrayList<Thread>()
+
     val memsize = minOf(USER_SPACE_SIZE, _memsize.toLong())
-    private val MALLOC_UNIT = 64
+    val MALLOC_UNIT = 64
     private val mallocBlockSize = (memsize / MALLOC_UNIT).toInt()
 
     internal val usermem = UnsafeHelper.allocate(memsize)
@@ -57,7 +61,15 @@ class VM(
         init()
     }
 
+    fun killAllContexts() {
+        contexts.forEach { it.interrupt() }
+        contexts.clear()
+    }
+
     fun init() {
+        killAllContexts()
+
+
         peripheralTable[0] = PeripheralEntry(
             IOSpace(this),
             HW_RESERVE_SIZE,
@@ -83,6 +95,7 @@ class VM(
     }
 
     fun dispose() {
+        killAllContexts()
         usermem.destroy()
         peripheralTable.forEach { it.peripheral?.dispose() }
     }
@@ -151,6 +164,7 @@ class VM(
 
     private val mallocMap = BitSet(mallocBlockSize)
     private val mallocSizes = HashMap<Int, Int>() // HashMap<Block Index, Block Count>
+    var allocatedBlockCount = 0; private set
 
     private fun findEmptySpace(blockSize: Int): Int? {
         var cursorHead = 0
@@ -180,6 +194,7 @@ class VM(
         val allocBlocks = ceil(size.toDouble() / MALLOC_UNIT).toInt()
         val blockStart = findEmptySpace(allocBlocks) ?: throw OutOfMemoryError()
 
+        allocatedBlockCount += allocBlocks
         mallocSizes[blockStart] = allocBlocks
         return blockStart * MALLOC_UNIT
     }
@@ -190,6 +205,7 @@ class VM(
 
         mallocMap.set(index, index + count, false)
         mallocSizes.remove(index)
+        allocatedBlockCount -= count
     }
 
     internal data class VMNativePtr(val address: Int, val size: Int)

tsvm_core/src/net/torvald/tsvm/VMJSR223Delegate.kt

@@ -1,5 +1,8 @@
 package net.torvald.tsvm
 
+import kotlinx.coroutines.GlobalScope
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.launch
 import net.torvald.terrarum.modulecomputers.virtualcomputer.tvd.toUlong
 import java.nio.charset.Charset
 
@@ -140,10 +143,32 @@ class VMJSR223Delegate(val vm: VM) {
     }
     fun waitForMemChg(addr: Int, andMask: Int) = waitForMemChg(addr, andMask, 0)
 
+    fun getUsedMem() = vm.allocatedBlockCount * vm.MALLOC_UNIT
 }
 
 class VMSerialDebugger(val vm: VM) {
     fun print(s: Any?) = System.out.print("$s")
     fun println(s: Any?) = System.out.println("$s")
     fun printerr(s: Any?) = System.err.println("$s")
+}
+
+class Parallel(val vm: VM) {
+    fun spawnNewContext(): VMRunner {
+        return VMRunnerFactory(vm.assetsDir, vm, "js")
+    }
+    fun attachProgram(context: VMRunner, program: String): Thread {
+        Thread { context.eval(program) }.let {
+            vm.contexts.add(it)
+            return it
+        }
+    }
+    fun launch(thread: Thread) {
+        thread.start()
+    }
+    fun suspend(thread: Thread) {
+        thread.suspend()
+    }
+    fun resume(thread: Thread) {
+        thread.resume()
+    }
 }

tsvm_core/src/net/torvald/tsvm/VMRunnerFactory.kt

@@ -8,6 +8,7 @@ import javax.script.ScriptEngineManager
 abstract class VMRunner(val extension: String) {
     abstract suspend fun executeCommand(command: String)
     abstract suspend fun evalGlobal(command: String)
+    abstract fun eval(command: String)
     abstract fun close()
 }
 
@@ -65,6 +66,7 @@ object VMRunnerFactory {
                         bind.putMember("base64", Base64Delegate)
                         bind.putMember("com", SerialHelperDelegate(vm))
                         bind.putMember("dma", DMADelegate(vm))
+                        bind.putMember("parallel", Parallel(vm))
 
                         val fr = FileReader("$assetsRoot/JS_INIT.js")
                         val prg = fr.readText()
@@ -83,6 +85,16 @@ object VMRunnerFactory {
                         }
                     }
 
+                    override fun eval(command: String) {
+                        try {
+                            context.eval("js", encapsulateJS(sanitiseJS(command)))
+                        }
+                        catch (e: javax.script.ScriptException) {
+                            System.err.println("ScriptException from the script:")
+                            System.err.println(command.substring(0, minOf(1024, command.length)))
+                            throw e
+                        }                    }
+
                     override suspend fun evalGlobal(command: String) {
                         context.eval("js", "\"use strict\";" + sanitiseJS(command))
                     }