Refactor PlatformSpecific functions with time and setTimeout, optimize RewindStep substeps handling, update MTMCClock timing logic, enhance frame processing, and integrate updateJsDisplay for dynamic updates in Main.

.idea/runConfigurations/MTMC_debug.xml

@@ -0,0 +1,7 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="MTMC debug" type="JavascriptDebugType" uri="http://localhost:4001/">
+    <method v="2">
+      <option name="Gradle.BeforeRunTask" enabled="true" tasks="jsBrowserDevelopmentExecutableDistribution" externalProjectPath="$PROJECT_DIR$" vmOptions="" scriptParameters="" />
+    </method>
+  </configuration>
+</component>

.idea/runConfigurations/MainKt.xml

@@ -0,0 +1,10 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="MainKt" type="JetRunConfigurationType" nameIsGenerated="true">
+    <option name="MAIN_CLASS_NAME" value="mtmc.MainKt" />
+    <module name="mtmc-web.jvmMain" />
+    <shortenClasspath name="NONE" />
+    <method v="2">
+      <option name="Make" enabled="true" />
+    </method>
+  </configuration>
+</component>

LICENSE.txt

@@ -0,0 +1,13 @@
+Zero-Clause BSD
+=============
+
+Permission to use, copy, modify, and/or distribute this software for
+any purpose with or without fee is hereby granted.
+
+THE SOFTWARE IS PROVIDED “AS IS” AND THE AUTHOR DISCLAIMS ALL
+WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
+OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE
+FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY
+DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
+AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
+OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

build.gradle.kts

@@ -1,5 +1,6 @@
 @file:OptIn(ExperimentalDistributionDsl::class)
 
+import org.jetbrains.kotlin.gradle.ExperimentalKotlinGradlePluginApi
 import org.jetbrains.kotlin.gradle.targets.js.dsl.ExperimentalDistributionDsl
 
 plugins {
@@ -21,7 +22,15 @@ repositories {
 
 kotlin {
   jvmToolchain(21)
-  jvm()
+  jvm {
+    @OptIn(ExperimentalKotlinGradlePluginApi::class)
+    binaries {
+      // Configures a JavaExec task named "runJvm" and a Gradle distribution for the "main" compilation in this target
+      executable {
+        mainClass.set("mtmc.MainKt")
+      }
+    }
+  }
   js {
     binaries.executable()
     browser {
@@ -40,9 +49,6 @@ kotlin {
     val commonMain by getting {
       dependencies {
         api("nl.astraeus:kotlin-simple-logging:1.1.1")
-        api("nl.astraeus:kotlin-css-generator:1.0.10")
-
-        implementation("org.jetbrains.kotlinx:kotlinx-datetime:0.6.0")
       }
     }
     val commonTest by getting
@@ -67,9 +73,9 @@ kotlin {
     }
     val jsMain by getting {
       dependencies {
-        implementation("nl.astraeus:kotlin-komponent:1.2.5")
+        implementation("nl.astraeus:kotlin-komponent:1.2.8")
       }
     }
     val jsTest by getting
   }
-}
+}

gradle/wrapper/gradle-wrapper.properties

@@ -1,6 +1,6 @@
 #Sun Apr 28 09:54:33 CEST 2024
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-8.5-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.11-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists

src/commonMain/kotlin/mtmc/asm/Assembler.kt

@@ -400,7 +400,7 @@ class Assembler {
   ): Graphic {
     val graphic = Graphic(labelTokens, token.line)
     val filename = token.stringValue
-    val file = File(File(this.srcName).getParent(), filename)
+    val file = File(File(this.srcName).parent, filename)
     val index = graphics.size
 
     data.setValue(token, byteArrayOf(((index shr 8) and 0xFF).toByte(), (index and 0xFF).toByte()))
@@ -732,7 +732,7 @@ class Assembler {
         val first = tokenizer!!.consume()
         tokens.add(first)
         while (tokenizer!!.more() &&
-          first.line == tokenizer!!.currentToken().line
+          first.line == tokenizer!!.getCurrentToken().line
         ) {
           tokens.add(tokenizer!!.consume())
         }

src/commonMain/kotlin/mtmc/asm/data/Data.kt

@@ -34,4 +34,4 @@ class Data(labels: MutableList<MTMCToken>, lineNumber: Int) : ASMElement(labels,
   override fun addError(err: String) {
     addError(labels.last(), err)
   }
-}
+}

src/commonMain/kotlin/mtmc/asm/instructions/Instruction.kt

@@ -57,7 +57,7 @@ abstract class Instruction(
       if (ls != null) {
         return ls
       }
-      val jumpReg = JumpInstruction.disassemble(instruction)
+      val jumpReg = JumpRegisterInstruction.disassemble(instruction)
       if (jumpReg != null) {
         return jumpReg
       }
@@ -65,7 +65,7 @@ abstract class Instruction(
       if (jump != null) {
         return jump
       }
-      return "<unknown>"
+      return ""
     }
   }
 }

src/commonMain/kotlin/mtmc/asm/instructions/JumpRegisterInstruction.kt

@@ -26,10 +26,16 @@ class JumpRegisterInstruction(
 
   companion object {
     fun disassemble(instruction: Short): String? {
-      if (BinaryUtils.getBits(16, 5, instruction).toInt() == 9) {
+      if (BinaryUtils.getBits(16, 4, instruction).toInt() == 9) {
         val reg = BinaryUtils.getBits(4, 4, instruction)
-        val sb = StringBuilder("jr")
-        sb.append(fromInteger(reg.toInt()))
+        if (reg.toInt() == 11) {
+          return "ret"
+        } else {
+          val sb = StringBuilder("jr")
+          sb.append(" ")
+          sb.append(fromInteger(reg.toInt()))
+          return sb.toString()
+        }
       }
       return null
     }

src/commonMain/kotlin/mtmc/emulator/BufferedImage.kt

@@ -0,0 +1,20 @@
+package mtmc.emulator
+
+expect fun createBufferedImage(width: Int, height: Int): BufferedImage
+
+expect fun createCanvasImage(width: Int, height: Int): BufferedImage
+
+expect fun createGLImage(width: Int, height: Int): BufferedImage
+
+interface BufferedImage {
+  val width: Int
+  val height: Int
+
+  fun getRGB(x: Int, y: Int): Int
+  fun setRGB(x: Int, y: Int, intVal: Int)
+}
+
+class Dimension(
+  val width: Int,
+  val height: Int
+)

src/commonMain/kotlin/mtmc/emulator/Color.kt

@@ -0,0 +1,8 @@
+package mtmc.emulator
+
+class Color(
+  val r: Int,
+  val g: Int,
+  val b: Int,
+) {
+}

src/commonMain/kotlin/mtmc/emulator/MTMCClock.kt

@@ -2,7 +2,11 @@ package mtmc.emulator
 
 import mtmc.emulator.MonTanaMiniComputer.ComputerStatus
 import mtmc.util.currentTimeMillis
+import mtmc.util.requestAnimationFrame
+import mtmc.util.setTimeout
+import mtmc.util.time
 import kotlin.math.max
+import kotlin.math.min
 
 /**
  *
@@ -11,49 +15,66 @@ import kotlin.math.max
 class MTMCClock(
   private val computer: MonTanaMiniComputer
 ) {
+  var instructions: Long = 0
+  var ips: Long = 0
+  var expected: Long = 0
+  var virtual: Long = 0
+
+  var startTime = currentTimeMillis()
+  var lastFrame = 0.0
+
+  var speed: Long = 0
+
+  var instructionsToRun = 0.0
+  var frame = 0
+
   fun run() {
-    var instructions: Long = 0
-    var ips: Long = 0
-    var expected: Long = 0
-    var virtual: Long = 0
+    requestAnimationFrame { handleFrame() }
+  }
 
-    var startTime = currentTimeMillis()
-    var deltaStart: Long
-    var delta: Long
+  fun handleFrame() {
+    // figure out how many instructions to execute this 'time' duration
+    // maximize time so we don't hang if the emulator is too slow
+    val time = time()
+    if (lastFrame == 0.0) {
+      lastFrame = time
+      requestAnimationFrame { handleFrame() }
+      return
+    }
+    val delta = time - lastFrame
+    lastFrame = time
 
-    var speed: Long = 0
-    var pulse: Long
-    var ms: Long = 10
+    val timeToProcess = min(delta, 16.0)
 
-    while (computer.getStatus() == ComputerStatus.EXECUTING) {
+    // assume 1Hz = 1 instruction/second
+    if (computer.getStatus() == ComputerStatus.EXECUTING) {
       speed = max(computer.speed, 0).toLong()
-      pulse = (if (speed <= 0) 1000000 else max(speed / 100, 1))
-      ms = (if (pulse < 10) 1000 / speed else 10)
-
-      deltaStart = currentTimeMillis()
-      delta = ms - (currentTimeMillis() - deltaStart)
-
-
-      /* We've lost more than a second. Recalibrate. */
-      if ((expected - virtual) > pulse * 100) {
-        startTime = deltaStart
-        virtual = 0
+      if (speed == 0L) {
+        speed = 1L
       }
 
+      instructionsToRun += timeToProcess * speed / 1000.0
+      val pulse: Long = instructionsToRun.toLong() + 1
+      instructionsToRun -= pulse
 
-      /* Throttles to every 10ms, but "catches up" if we're behind */
-      if (delta > 0 && (expected - virtual) < pulse && speed != 0L) {
-        try {
-          Thread.sleep(delta)
-        } catch (e: InterruptedException) {
-        }
+      val start = time()
+      val ir = computer.pulse(pulse)
+      instructions += ir
+      val duration = (time() - start)
+      val actual = ir / (delta / 1000.0)
+      if (frame % 100 == 0) {
+        println("Instructions ran: $ir (delta = ${delta.toFloat()}, timeToProcess = ${timeToProcess.toFloat()}, speed = $speed (actual=${actual.toLong()}), duration = $duration)")
       }
 
-      instructions += computer.pulse(pulse)
+      virtual += instructions
+      ips = (instructions / timeToProcess).toLong()
+      frame++
 
-      virtual += pulse
-      ips = (virtual * 1000) / max(1, currentTimeMillis() - startTime)
-      expected = (currentTimeMillis() - startTime) * speed / 1000
+      if (duration > timeToProcess) {
+        setTimeout({ handleFrame() })
+      } else {
+        requestAnimationFrame { handleFrame() }
+      }
     }
 
     //println("Executed " + instructions + " instructions at a rate of " + ips + " ips (speed = " + speed + ")")

src/commonMain/kotlin/mtmc/emulator/MTMCConsole.kt

@@ -1,17 +1,16 @@
 package mtmc.emulator
 
 import mtmc.os.fs.Console
-import mtmc.os.fs.System
 import mtmc.os.shell.Shell
 import mtmc.tokenizer.MTMCScanner
 import mtmc.tokenizer.MTMCToken
 
 class MTMCConsole(private val computer: MonTanaMiniComputer) {
-  var mode: Mode = Mode.NON_INTERACTIVE
+  var mode: Mode = Mode.INTERACTIVE
   var sysConsole: Console? = null
 
   // non-interactive data
-  private val output = StringBuilder()
+  private var output = StringBuilder()
   private var shortValueSet = false
   private var shortValue: Short = 0
   private var stringValue: String? = null
@@ -19,12 +18,7 @@ class MTMCConsole(private val computer: MonTanaMiniComputer) {
   // TODO invert so shell is driving and console is just IO
   fun start() {
     mode = Mode.INTERACTIVE
-    sysConsole = System.console
     Shell.printShellWelcome(computer)
-    while (true) {
-      val cmd = sysConsole!!.readLine("mtmc > ")
-      computer.oS.processCommand(cmd)
-    }
   }
 
   fun println(x: String) {
@@ -89,7 +83,9 @@ class MTMCConsole(private val computer: MonTanaMiniComputer) {
     val text = if (index >= 0) output.substring(0, index + 1) else ""
 
     if (index >= 0) {
-      output.removeRange(0, index + 1)
+      val updated = StringBuilder()
+      updated.append(output.removeRange(0, index + 1))
+      output = updated
     }
 
     return text
@@ -122,7 +118,7 @@ class MTMCConsole(private val computer: MonTanaMiniComputer) {
   }
 
   fun resetOutput() {
-    output.removeRange(0, output.length)
+    output.clear()
   }
 
   enum class Mode {

src/commonMain/kotlin/mtmc/emulator/MonTanaMiniComputer.kt

@@ -18,7 +18,7 @@ class MonTanaMiniComputer {
   var memory: ByteArray = ByteArray(MEMORY_SIZE)
   var breakpoints: ByteArray = ByteArray(MEMORY_SIZE)
   private var status: ComputerStatus? = ComputerStatus.READY
-  var speed: Int = 1000000
+  var speed: Int = 1
     set(speed) {
       field = speed
       this.notifyOfExecutionUpdate()
@@ -31,7 +31,9 @@ class MonTanaMiniComputer {
   var display: MTMCDisplay = MTMCDisplay(this)
   var clock: MTMCClock = MTMCClock(this)
   var fileSystem: FileSystem = FileSystem(this)
-  var rewindSteps = mutableListOf<RewindStep>()
+
+  var rewindSteps = Array(MAX_REWIND_STEPS) { RewindStep() }
+  var rewindIndex = -1
 
   // listeners
   private val observers = mutableListOf<MTMCObserver>()
@@ -46,34 +48,33 @@ class MonTanaMiniComputer {
     registerFile = ShortArray(Register.entries.size)
     memory = ByteArray(MEMORY_SIZE)
     breakpoints = ByteArray(MEMORY_SIZE)
-    rewindSteps.clear()
     setRegisterValue(
       Register.SP,
       MEMORY_SIZE.toShort().toInt()
     ) // default the stack pointer to the top of memory
-    rewindSteps.clear()
+    rewindIndex = -1
     observers.forEach { obj ->
       obj.computerReset()
     }
   }
 
-  fun load(code: ByteArray, data: ByteArray, debugInfo: DebugInfo?) {
-    load(code, data, Array(0) { ByteArray(0) }, debugInfo)
-  }
-
-  fun load(code: ByteArray, data: ByteArray, graphics: Array<ByteArray>, debugInfo: DebugInfo?) {
+  fun load(
+    code: ByteArray,
+    data: ByteArray,
+    graphics: Array<ByteArray> = arrayOf(),
+    debugInfo: DebugInfo? = null
+  ) {
     this.debugInfo = debugInfo
 
     // reset memory
     initMemory()
 
-
     val codeBoundary = code.size
     code.copyInto(memory, 0, 0, codeBoundary)
     setRegisterValue(Register.CB, codeBoundary - 1)
 
     val dataBoundary = codeBoundary + data.size
-    code.copyInto(memory, codeBoundary, 0, data.size)
+    data.copyInto(memory, codeBoundary, 0, data.size)
     setRegisterValue(Register.DB, dataBoundary - 1)
 
 
@@ -132,10 +133,9 @@ class MonTanaMiniComputer {
   }
 
   fun fetchAndExecute() {
-    currentRewindStep = RewindStep()
-    currentRewindStep?.let {
-      rewindSteps.add(0, it)
-    }
+    rewindIndex = (rewindIndex + 1) % rewindSteps.size
+    rewindSteps[rewindIndex].index = 0
+
     fetchCurrentInstruction()
     val instruction = getRegisterValue(Register.IR)
     if (isDoubleWordInstruction(instruction)) {
@@ -727,7 +727,11 @@ class MonTanaMiniComputer {
   private fun badInstruction(instruction: Short) {
     setStatus(ComputerStatus.PERMANENT_ERROR)
     // TODO implement flags
-    console.println("BAD INSTRUCTION: 0x" + (instruction.toInt() and 0xFFFF).toHexString())
+    console.println(
+      "BAD INSTRUCTION: 0x" + (instruction.toHexString()) + " at PC " + getRegisterValue(
+        Register.PC
+      )
+    )
   }
 
   fun fetchCurrentInstruction() {
@@ -749,7 +753,7 @@ class MonTanaMiniComputer {
     val upperByte = fetchByteFromMemory(address).toShort()
     val lowerByte = fetchByteFromMemory(address + 1)
     var value = (upperByte.toInt() shl 8).toShort()
-    val i = value.toInt() or lowerByte.toInt()
+    val i = value.toInt() + (lowerByte.toInt() and 255)
     value = i.toShort()
     return value
   }
@@ -785,17 +789,14 @@ class MonTanaMiniComputer {
     val currentValue = memory[address]
     addRewindStep { memory[address] = currentValue }
     memory[address] = value
-    observers!!.forEach { o: MTMCObserver? ->
+    observers.forEach { o: MTMCObserver? ->
       o!!.memoryUpdated(address, value)
     }
   }
 
   private fun addRewindStep(runnable: Runnable?) {
-    if (currentRewindStep != null && rewindSteps != null) {
+    if (currentRewindStep != null) {
       currentRewindStep!!.addSubStep(runnable)
-      if (rewindSteps.size > MAX_REWIND_STEPS) {
-        rewindSteps.removeLast()
-      }
     }
   }
 
@@ -812,7 +813,7 @@ class MonTanaMiniComputer {
       registerFile[register] = currentValue
     }
     registerFile[register] = value.toShort()
-    observers!!.forEach { o: MTMCObserver? ->
+    observers.forEach { o: MTMCObserver? ->
       o!!.registerUpdated(register, value)
     }
   }
@@ -843,7 +844,7 @@ class MonTanaMiniComputer {
     breakpoints[address] = (if (active) 1.toByte() else 0.toByte())
   }
 
-  private fun start() {
+  fun start() {
     console.start() // start the interactive console
   }
 
@@ -950,12 +951,15 @@ class MonTanaMiniComputer {
   }
 
   fun rewind() {
-    val latestRewindStep = rewindSteps.removeFirst()
-    latestRewindStep.rewind()
+    if (rewindIndex >= 0) {
+      val latestRewindStep = rewindSteps[rewindIndex]
+      rewindIndex--
+      latestRewindStep?.rewind()
+    }
   }
 
   val isBackAvailable: Boolean
-    get() = !rewindSteps!!.isEmpty()
+    get() = rewindIndex >= 0
 
   enum class ComputerStatus {
     READY,
@@ -1011,16 +1015,8 @@ class MonTanaMiniComputer {
         return true
       }
       val isMcp = getBits(16, 8, instruction) == 5.toShort()
-      if (isMcp) {
-        return true
-      }
-      return false
-    }
 
-    fun main(args: Array<String>) {
-      val computer = MonTanaMiniComputer()
-      computer.speed = 1 // default to 1hz
-      computer.start()
+      return isMcp
     }
   }
 }

src/commonMain/kotlin/mtmc/emulator/RewindStep.kt

@@ -3,13 +3,16 @@ package mtmc.emulator
 import mtmc.util.Runnable
 
 class RewindStep {
-  var subSteps: MutableList<Runnable?> = ArrayList<Runnable?>()
+  var subSteps: Array<Runnable> = Array(10) { {} }
+  var index = 0
 
   fun rewind() {
     subSteps.reversed().forEach({ obj: Runnable? -> obj!!.invoke() })
   }
 
   fun addSubStep(subStep: Runnable?) {
-    subSteps.add(subStep)
+    if (subStep != null && index < subSteps.size) {
+      subSteps[index++] = subStep
+    }
   }
 }

src/commonMain/kotlin/mtmc/os/MTOS.kt

@@ -12,7 +12,7 @@ import kotlin.math.min
 import kotlin.random.Random
 
 class MTOS(private val computer: MonTanaMiniComputer) {
-  private var timer: Long = 0
+  private var timer: Double = 0.0
   var random: Random = Random.Default
 
   // Editor support
@@ -51,59 +51,59 @@ class MTOS(private val computer: MonTanaMiniComputer) {
   fun handleSysCall(syscallNumber: Short) {
     if (syscallNumber == getValue("exit").toShort()) {
       computer.setStatus(MonTanaMiniComputer.ComputerStatus.FINISHED)
-    } else if (syscallNumber == getValue("rint").toShort()) {
-      // rint
-      if (!computer.console.hasShortValue()) {
-        computer.notifyOfRequestInteger()
-      }
-      while (!computer.console.hasShortValue() && computer.getStatus() == MonTanaMiniComputer.ComputerStatus.EXECUTING) {
-        try {
-          Thread.sleep(10)
-        } catch (e: InterruptedException) {
-        }
-      }
-      val `val` = computer.console.readInt()
-      computer.setRegisterValue(Register.RV, `val`.toInt())
+//    } else if (syscallNumber == getValue("rint").toShort()) {
+//      // rint
+//      if (!computer.console.hasShortValue()) {
+//        computer.notifyOfRequestInteger()
+//      }
+//      while (!computer.console.hasShortValue() && computer.getStatus() == MonTanaMiniComputer.ComputerStatus.EXECUTING) {
+//        try {
+//          Thread.sleep(10)
+//        } catch (e: InterruptedException) {
+//        }
+//      }
+//      val `val` = computer.console.readInt()
+//      computer.setRegisterValue(Register.RV, `val`.toInt())
     } else if (syscallNumber == getValue("wint").toShort()) {
       // wint
       val value = computer.getRegisterValue(Register.A0)
       computer.console.writeInt(value)
-    } else if (syscallNumber == getValue("rchr").toShort()) {
-      if (!computer.console.hasShortValue()) {
-        computer.notifyOfRequestCharacter()
-      }
-      while (!computer.console.hasShortValue() && computer.getStatus() == MonTanaMiniComputer.ComputerStatus.EXECUTING) {
-        try {
-          Thread.sleep(10)
-        } catch (e: InterruptedException) {
-        }
-      }
-      val `val` = computer.console.readChar()
-      computer.setRegisterValue(Register.RV, `val`.code)
+//    } else if (syscallNumber == getValue("rchr").toShort()) {
+//      if (!computer.console.hasShortValue()) {
+//        computer.notifyOfRequestCharacter()
+//      }
+//      while (!computer.console.hasShortValue() && computer.getStatus() == MonTanaMiniComputer.ComputerStatus.EXECUTING) {
+//        try {
+//          Thread.sleep(10)
+//        } catch (e: InterruptedException) {
+//        }
+//      }
+//      val `val` = computer.console.readChar()
+//      computer.setRegisterValue(Register.RV, `val`.code)
     } else if (syscallNumber == getValue("wchr").toShort()) {
       val value = computer.getRegisterValue(Register.A0)
       computer.console.print("" + Char(value.toUShort()))
-    } else if (syscallNumber == getValue("rstr").toShort()) {
-      // rstr
-      val pointer = computer.getRegisterValue(Register.A0)
-      val maxLen = computer.getRegisterValue(Register.A1)
-      if (!computer.console.hasReadString()) {
-        computer.notifyOfRequestString()
-      }
-      while (!computer.console.hasReadString() && computer.getStatus() == MonTanaMiniComputer.ComputerStatus.EXECUTING) {
-        try {
-          Thread.sleep(10)
-        } catch (e: InterruptedException) {
-        }
-      }
-      val string = computer.console.readString()
-      val bytes = string!!.encodeToByteArray()
-      val bytesToRead = min(bytes.size, maxLen.toInt())
-      for (i in 0..<bytesToRead) {
-        val aByte = bytes[i]
-        computer.writeByteToMemory(pointer + i, aByte)
-      }
-      computer.setRegisterValue(Register.RV, bytesToRead)
+//    } else if (syscallNumber == getValue("rstr").toShort()) {
+//      // rstr
+//      val pointer = computer.getRegisterValue(Register.A0)
+//      val maxLen = computer.getRegisterValue(Register.A1)
+//      if (!computer.console.hasReadString()) {
+//        computer.notifyOfRequestString()
+//      }
+//      while (!computer.console.hasReadString() && computer.getStatus() == MonTanaMiniComputer.ComputerStatus.EXECUTING) {
+//        try {
+//          Thread.sleep(10)
+//        } catch (e: InterruptedException) {
+//        }
+//      }
+//      val string = computer.console.readString()
+//      val bytes = string!!.encodeToByteArray()
+//      val bytesToRead = min(bytes.size, maxLen.toInt())
+//      for (i in 0..<bytesToRead) {
+//        val aByte = bytes[i]
+//        computer.writeByteToMemory(pointer + i, aByte)
+//      }
+//      computer.setRegisterValue(Register.RV, bytesToRead)
     } else if (syscallNumber == getValue("wstr").toShort()) {
       // wstr
       val pointer = computer.getRegisterValue(Register.A0)
@@ -171,14 +171,14 @@ class MTOS(private val computer: MonTanaMiniComputer) {
       }
 
       computer.setRegisterValue(Register.RV, random.nextInt(low.toInt(), high + 1))
-    } else if (syscallNumber == getValue("sleep").toShort()) {
-      // sleep
-      val millis = computer.getRegisterValue(Register.A0)
-      try {
-        if (millis > 0) Thread.sleep(millis.toLong())
-      } catch (e: InterruptedException) {
-        throw RuntimeException(e)
-      }
+//    } else if (syscallNumber == getValue("sleep").toShort()) {
+//      // sleep
+//      val millis = computer.getRegisterValue(Register.A0)
+//      try {
+//        if (millis > 0) Thread.sleep(millis.toLong())
+//      } catch (e: InterruptedException) {
+//        throw RuntimeException(e)
+//      }
     } else if (syscallNumber == getValue("fbreset").toShort()) {
       // fbreset
       computer.display.reset()
@@ -240,7 +240,38 @@ class MTOS(private val computer: MonTanaMiniComputer) {
       try {
         // special handling for game-of-life cell files
         if ("cells" == fileType) {
-          val str = Files.readString(file.toPath())
+          //val str = Files.readString(file.toPath())
+          val str = """
+            ! galaxy
+            ! Kok's galaxy - a whirling oscillator
+            .......................................
+            .......................................
+            .......................................
+            .......................................
+            .......................................
+            .......................................
+            .......................................
+            .......................................
+            .......................................
+            .......................................
+            .......................................
+            .......................................
+            .......................................
+            ...............OOOOOO.OO.....
+            ...............OOOOOO.OO
+            ......................OO
+            ...............OO.....OO
+            ...............OO.....OO
+            ...............OO.....OO
+            ...............OO.......
+            ...............OO.OOOOOO
+            ...............OO.OOOOOO.......................................
+            .......................................
+            .......................................
+            .......................................
+            .......................................
+            .......................................
+          """.trimIndent()
           val lines: List<String> =
             str.split("\n".toRegex()).dropLastWhile { it.isEmpty() }.toTypedArray()
             .filter { s: String? -> !s!!.startsWith("!") }
@@ -309,7 +340,7 @@ class MTOS(private val computer: MonTanaMiniComputer) {
 
       computer.setRegisterValue(
         Register.RV,
-        max(0, this.timer - currentTimeMillis()).toInt()
+        max(0.0, this.timer - currentTimeMillis()).toInt()
       )
     } else if (syscallNumber == getValue("drawimg").toShort()) {
       val image = computer.getRegisterValue(Register.A0)

src/commonMain/kotlin/mtmc/os/fs/File.kt

@@ -16,21 +16,17 @@ class File(
   val name: String
 ) {
 
-  var directory: Boolean = TODO("initialize me")
+  var directory: Boolean = false
 
   constructor(name: String) : this(null, name)
 
-  fun getParent(): File = parent ?: error("No parent")
-
   fun getPath(): String = if (parent == null) {
     name
   } else {
     "${parent.getPath()}/$name"
   }
 
-  fun exists(): Boolean {
-    TODO("Not yet implemented")
-  }
+  fun exists(): Boolean = true
 
   fun getAbsolutePath(): String {
     TODO("Not yet implemented")

src/commonMain/kotlin/mtmc/os/fs/Path.kt

@@ -12,4 +12,14 @@ class Path {
   fun resolve(filename: String): Path {
     TODO("Not yet implemented")
   }
+
+  fun toAbsolutePath(): Path {
+    TODO("Not yet implemented")
+  }
+
+  companion object {
+    fun of(string: String): Path {
+      TODO()
+    }
+  }
 }

src/commonMain/kotlin/mtmc/os/shell/Shell.kt

@@ -77,6 +77,7 @@ object Shell {
   }
 
   fun execCommand(command: String, computer: MonTanaMiniComputer) {
+    println("Exec: $command")
     val tokens = MTMCTokenizer(command, "#")
     try {
       val identifier = tokens.matchAndConsume(MTMCToken.TokenType.IDENTIFIER)
@@ -96,17 +97,18 @@ object Shell {
           return
         }
       } else {
-        cmd = identifier.stringValue()
+        cmd = identifier.stringValue
       }
       if (isCommand(cmd)) {
         COMMANDS[cmd.lowercase()]!!.exec(tokens, computer)
       } else {
+        println("Executing: $command")
         tokens.reset()
         val asm = mutableListOf<MTMCToken>()
         asm.addAll(tokens.tokens)
         val updatedAsm = Assembler.transformSyntheticInstructions(asm)
         val firstToken = updatedAsm.peekFirst()
-        val firstTokenStr = firstToken?.stringValue() ?: error("Unexpected null token")
+        val firstTokenStr = firstToken?.stringValue ?: error("Unexpected null token")
         if (!updatedAsm.isEmpty() && isInstruction(firstTokenStr)) {
           val assembler = Assembler()
           val result = assembler.assemble(command)

src/commonMain/kotlin/mtmc/os/shell/builtins/GetCommand.kt

@@ -17,11 +17,11 @@ class GetCommand : ShellCommand() {
     if (memLocation == null) {
       val register = tokens.matchAndConsume(MTMCToken.TokenType.IDENTIFIER)
       if (register == null) usageException()
-      val reg = Register.toInteger(register!!.stringValue())
+      val reg = Register.toInteger(register!!.stringValue)
       if (reg >= 0) {
-        computer.console.println(register.stringValue() + ": " + computer.getRegisterValue(reg))
+        computer.console.println(register.stringValue + ": " + computer.getRegisterValue(reg))
       } else {
-        throw IllegalArgumentException("Bad register: " + register.stringValue())
+        throw IllegalArgumentException("Bad register: " + register.stringValue)
       }
     } else {
       if (memLocation.type === MTMCToken.TokenType.INTEGER || memLocation.type === MTMCToken.TokenType.BINARY || memLocation.type === MTMCToken.TokenType.HEX) {

src/commonMain/kotlin/mtmc/os/shell/builtins/SetCommand.kt

@@ -23,11 +23,11 @@ class SetCommand : ShellCommand() {
         MTMCToken.TokenType.BINARY
       )
       if (value == null) usageException()
-      val reg = Register.toInteger(register!!.stringValue())
+      val reg = Register.toInteger(register!!.stringValue)
       if (reg >= 0) {
         computer.setRegisterValue(reg, value!!.intValue())
       } else {
-        throw IllegalArgumentException("Bad register: " + register.stringValue())
+        throw IllegalArgumentException("Bad register: " + register.stringValue)
       }
     } else {
       val value = tokens.matchAndConsume(
@@ -42,7 +42,7 @@ class SetCommand : ShellCommand() {
       } else {
         computer.writeStringToMemory(
           memLocation.intValue(),
-          value!!.stringValue().encodeToByteArray()
+          value!!.stringValue.encodeToByteArray()
         )
       }
     }

src/commonMain/kotlin/mtmc/tokenizer/MTMCToken.kt

@@ -12,10 +12,6 @@ data class MTMCToken(
     return stringValue
   }
 
-  fun stringValue(): String {
-    return stringValue
-  }
-
   fun charValue(): Char {
     return stringValue.get(0)
   }

src/commonMain/kotlin/mtmc/tokenizer/MTMCTokenizer.kt

@@ -7,7 +7,7 @@ class MTMCTokenizer(var source: String, lineCommentStart: String) {
   var tokens: MutableList<MTMCToken> = MTMCScanner(source, lineCommentStart).tokenize()
   var currentToken: Int = 0
 
-  fun currentToken(): MTMCToken {
+  fun getCurrentToken(): MTMCToken {
     return tokens.get(currentToken)
   }
 
@@ -28,8 +28,8 @@ class MTMCTokenizer(var source: String, lineCommentStart: String) {
   }
 
   fun matchAndConsume(identifier: String?): Boolean {
-    if (currentToken().type == MTMCToken.TokenType.IDENTIFIER &&
-      currentToken().stringValue == identifier
+    if (getCurrentToken().type == MTMCToken.TokenType.IDENTIFIER &&
+      getCurrentToken().stringValue == identifier
     ) {
       return true
     } else {
@@ -39,7 +39,7 @@ class MTMCTokenizer(var source: String, lineCommentStart: String) {
 
   fun match(vararg type: MTMCToken.TokenType?): Boolean {
     for (tokenType in type) {
-      if (currentToken().type == tokenType) {
+      if (getCurrentToken().type == tokenType) {
         return true
       }
     }
@@ -51,7 +51,7 @@ class MTMCTokenizer(var source: String, lineCommentStart: String) {
   }
 
   fun more(): Boolean {
-    return currentToken().type != MTMCToken.TokenType.EOF
+    return getCurrentToken().type != MTMCToken.TokenType.EOF
   }
 
   fun previousToken(): MTMCToken? {
@@ -83,7 +83,7 @@ class MTMCTokenizer(var source: String, lineCommentStart: String) {
       do {
         last = consume()
         sb.append(last.stringValue)
-        next = currentToken()
+        next = getCurrentToken()
       } while (more() && last.end == next.start)
       return sb.toString()
     } else {

src/commonMain/kotlin/mtmc/util/BinaryUtils.kt

@@ -11,13 +11,9 @@ object BinaryUtils {
       return 0
     }
     val returnValue = (value.toInt() and 0xffff) ushr (start - totalBits)
-    var mask = 0
-    var toShift = totalBits
-    while (toShift > 0) {
-      toShift--
-      mask = mask shl 1
-      mask = mask + 1
-    }
+    var mask = 1
+    mask = mask shl totalBits
+    mask--
     return (returnValue and mask).toShort()
   }
 

src/commonMain/kotlin/mtmc/util/PlatformSpecific.kt

@@ -1,3 +1,11 @@
 package mtmc.util
 
-expect fun currentTimeMillis(): Long
+expect fun currentTimeMillis(): Double
+
+expect fun time(): Double
+
+expect fun requestAnimationFrame(action: (Double) -> Unit)
+
+expect fun setTimeout(action: () -> Unit)
+
+expect fun immediateTimeout(action: (Double) -> Unit): Int

src/jsMain/kotlin/mtmc/Main.kt

@@ -1,18 +1,43 @@
 package mtmc
 
 import kotlinx.browser.document
-import kotlinx.html.div
-import nl.astraeus.komp.HtmlBuilder
+import kotlinx.browser.window
+import mtmc.emulator.MonTanaMiniComputer
+import mtmc.util.currentTimeMillis
+import mtmc.view.DisplayView
+import mtmc.view.MTMCView
 import nl.astraeus.komp.Komponent
 
-class HelloKomponent : Komponent() {
-  override fun HtmlBuilder.render() {
-    div {
-      + "Hello, world!"
-    }
-  }
-}
+val computer = MonTanaMiniComputer()
+val mainView = MTMCView(computer)
+val display = DisplayView(computer)
 
 fun main() {
-  Komponent.create(document.body!!, HelloKomponent())
+  computer.speed = 1000000
+  computer.load(lifeCode, lifeData)
+  //computer.load(snakeCode, snakeData)
+
+  Komponent.create(document.body!!, mainView)
+
+  computer.start()
+
+  mainView.requestUpdate()
+  display.requestUpdate()
+
+  window.requestAnimationFrame { updateJsDisplay() }
+}
+
+var lastMemoryUpdate = currentTimeMillis()
+var updateState = true
+
+fun updateJsDisplay() {
+  display.requestUpdate()
+  if (currentTimeMillis() - lastMemoryUpdate > 125) {
+    if (updateState) {
+      mainView.registerView.requestUpdate()
+      mainView.memoryView.requestUpdate()
+    }
+    lastMemoryUpdate = currentTimeMillis()
+  }
+  window.requestAnimationFrame { updateJsDisplay() }
 }

src/jsMain/kotlin/mtmc/emulator/BufferedImage.js.kt

@@ -0,0 +1,116 @@
+package mtmc.emulator
+
+import kotlinx.browser.document
+import org.khronos.webgl.Uint8Array
+import org.khronos.webgl.get
+import org.khronos.webgl.set
+import org.w3c.dom.CanvasRenderingContext2D
+import org.w3c.dom.HTMLCanvasElement
+import org.w3c.dom.ImageData
+
+actual fun createBufferedImage(
+  width: Int,
+  height: Int
+): BufferedImage = BufferedImageImpl(width, height, 1)
+
+class BufferedImageImpl(
+  override val width: Int,
+  override val height: Int,
+  val type: Int
+) : BufferedImage {
+  val display = ByteArray(width * height * 4)
+
+  override fun getRGB(x: Int, y: Int): Int {
+    check(x in 0 until width && y in 0 until height)
+
+    val offset = (x + y * width) * 4
+    return display[offset + 0].toInt() +
+        display[offset + 1].toInt() shl 8 +
+        display[offset + 2].toInt() shl 16
+  }
+
+  override fun setRGB(x: Int, y: Int, intVal: Int) {
+    check(x in 0 until width && y in 0 until height)
+
+    val offset = (x + y * width) * 4
+    display[offset + 0] = (intVal shr 16).toByte()
+    display[offset + 1] = (intVal shr 8).toByte()
+    display[offset + 2] = intVal.toByte()
+    display[offset + 3] = 255.toByte()
+  }
+}
+
+class BufferedImageData(
+  val imageData: ImageData,
+) : BufferedImage {
+  override val width: Int = imageData.width
+  override val height: Int = imageData.height
+
+  override fun getRGB(x: Int, y: Int): Int {
+    check(x in 0 until width && y in 0 until height)
+
+    val offset = (x * 4 + y * width * 4)
+    val display = imageData.data
+    return (display[offset + 0].toInt() and 0xff) shl 16 +
+        (display[offset + 1].toInt() and 0xff) shl 8 +
+        (display[offset + 2].toInt() and 0xff)
+  }
+
+  override fun setRGB(x: Int, y: Int, intVal: Int) {
+    check(x in 0 until width && y in 0 until height)
+
+    val offset = (x * 4 + y * width * 4)
+    val display = imageData.data
+    display[offset + 0] = ((intVal shr 16) and 0xff).toShort().asDynamic()
+    display[offset + 1] = ((intVal shr 8) and 0xff).toShort().asDynamic()
+    display[offset + 2] = (intVal and 0xff).toShort().asDynamic()
+    display[offset + 3] = 255.toShort().asDynamic()
+  }
+}
+
+class BufferedImageDataWebGl(
+  override val width: Int,
+  override val height: Int,
+  val data: Uint8Array = Uint8Array(width * height * 4)
+) : BufferedImage {
+  init {
+    for (x in 0 until width) {
+      for (y in 0 until height) {
+        val offset = (x * 4 + y * width * 4)
+        data[offset + 3] = 255.toShort().asDynamic()
+      }
+    }
+  }
+
+  override fun getRGB(x: Int, y: Int): Int {
+    check(x in 0 until width && y in 0 until height)
+
+    val offset = (x * 4 + y * width * 4)
+    val display = data
+    return (display[offset + 0].toInt() and 0xff) shl 16 +
+        (display[offset + 1].toInt() and 0xff) shl 8 +
+        (display[offset + 2].toInt() and 0xff) shl 0 + 255
+  }
+
+  override fun setRGB(x: Int, y: Int, intVal: Int) {
+    check(x in 0 until width && y in 0 until height)
+
+    val offset = (x * 4 + y * width * 4)
+
+    data[offset + 0] = ((intVal shr 16) and 0xff).toShort().asDynamic()
+    data[offset + 1] = ((intVal shr 8) and 0xff).toShort().asDynamic()
+    data[offset + 2] = ((intVal shr 0) and 0xff).toShort().asDynamic()
+    //data[offset + 3] = 255.toShort().asDynamic()
+  }
+}
+
+val canvas = document.createElement("canvas") as HTMLCanvasElement
+val ctx = canvas.getContext("2d") as CanvasRenderingContext2D
+
+actual fun createCanvasImage(width: Int, height: Int): BufferedImage {
+  return BufferedImageData(ctx.createImageData(width.toDouble(), height.toDouble()));
+}
+
+actual fun createGLImage(width: Int, height: Int): BufferedImage {
+  return BufferedImageDataWebGl(width, height)
+}

src/jsMain/kotlin/mtmc/util/PlatformSpecific.js.kt

@@ -1,5 +1,19 @@
 package mtmc.util
 
+import kotlinx.browser.window
 import kotlin.js.Date
 
-actual fun currentTimeMillis(): Long = Date().getTime().toLong()
+actual fun currentTimeMillis(): Double = Date().getTime()
+actual fun requestAnimationFrame(action: (Double) -> Unit) {
+  window.requestAnimationFrame {
+    action(it)
+  }
+}
+
+actual fun immediateTimeout(action: (Double) -> Unit): Int = window.setTimeout(action, 0)
+
+actual fun time(): Double = window.performance.now()
+
+actual fun setTimeout(action: () -> Unit) {
+  window.setTimeout(action)
+}

src/jsMain/kotlin/mtmc/view/ConsoleView.kt

@@ -0,0 +1,86 @@
+package mtmc.view
+
+import kotlinx.browser.window
+import kotlinx.html.div
+import kotlinx.html.input
+import kotlinx.html.js.onClickFunction
+import kotlinx.html.js.onKeyUpFunction
+import kotlinx.html.span
+import mtmc.display
+import mtmc.emulator.MonTanaMiniComputer
+import mtmc.mainView
+import mtmc.os.shell.Shell
+import nl.astraeus.komp.HtmlBuilder
+import nl.astraeus.komp.Komponent
+import nl.astraeus.komp.currentElement
+import org.w3c.dom.HTMLInputElement
+import org.w3c.dom.events.KeyboardEvent
+
+class ConsoleView(
+  val computer: MonTanaMiniComputer
+) : Komponent() {
+  var input: String = ""
+  var output = StringBuilder()
+  private var inputElement: HTMLInputElement? = null
+
+  init {
+    output.append(computer.console.consumeLines())
+  }
+
+  override fun HtmlBuilder.render() {
+    div("console") {
+      onClickFunction = {
+        inputElement?.focus()
+      }
+      div("console-history") {
+        div {
+          +output.toString()
+        }
+      }
+      div("console-input") {
+        span("console-prompt") {
+          +"mtmc$"
+        }
+        input(classes = "console-input") {
+          value = input
+          autoFocus = true
+          inputElement = currentElement() as? HTMLInputElement
+          currentElement().scrollIntoView()
+          window.setTimeout({
+            inputElement?.focus()
+          }, 0)
+          onKeyUpFunction = { it ->
+            (it as? KeyboardEvent)?.let { ke ->
+              (ke.target as? HTMLInputElement)?.let { inp ->
+                if (ke.key == "Enter") {
+                  handleCommand()
+                } else {
+                  input = inp.value
+                }
+              }
+            }
+          }
+        }
+      }
+    }
+  }
+
+  private fun handleCommand() {
+    computer.console.print("mtmc$ ")
+    computer.console.println(input)
+
+    Shell.execCommand(input, computer)
+
+    input = ""
+    output.append(computer.console.consumeLines())
+    if (output.length > 1000 && output.contains("\n")) {
+      output = output.deleteRange(0, output.indexOf("\n"))
+    }
+
+    mainView.registerView.requestUpdate()
+    mainView.memoryView.requestUpdate()
+    display.requestUpdate()
+    requestUpdate()
+  }
+
+}

src/jsMain/kotlin/mtmc/view/ControlView.kt

@@ -0,0 +1,157 @@
+package mtmc.view
+
+import kotlinx.html.InputType
+import kotlinx.html.button
+import kotlinx.html.div
+import kotlinx.html.i
+import kotlinx.html.input
+import kotlinx.html.js.onChangeFunction
+import kotlinx.html.js.onClickFunction
+import kotlinx.html.label
+import kotlinx.html.option
+import kotlinx.html.select
+import kotlinx.html.span
+import mtmc.display
+import mtmc.emulator.MonTanaMiniComputer
+import mtmc.mainView
+import mtmc.updateState
+import nl.astraeus.komp.HtmlBuilder
+import nl.astraeus.komp.Komponent
+import org.w3c.dom.HTMLSelectElement
+import kotlin.text.Typography.nbsp
+
+class ControlView(
+  val computer: MonTanaMiniComputer
+) : Komponent() {
+
+  override fun HtmlBuilder.render() {
+    div("control-panel") {
+      div("control-header") {
+        span {
+          +"m"
+        }
+        span {
+          +"s"
+        }
+        span {
+          +"u"
+        }
+        nbsp
+        i {
+          +"MTMC-16"
+        }
+      }
+      div("control-secondary") {
+        +"MonTana Mini-Computer"
+      }
+      div("control-buttons") {
+        label {
+          +"Update:"
+          htmlFor = "update-state"
+          input {
+            type = InputType.checkBox
+            checked = updateState
+            onClickFunction = {
+              updateState = !updateState
+              requestUpdate()
+            }
+          }
+        }
+        label {
+          select {
+            name = "speed"
+
+            option {
+              value = "1"
+              +"1 Hz"
+            }
+            option {
+              value = "10"
+              +"10 Hz"
+            }
+            option {
+              value = "100"
+              +"100 Hz"
+            }
+            option {
+              value = "1000"
+              +"1 Khz"
+            }
+            option {
+              value = "1000000"
+              selected = true
+              +"1 Mhz"
+            }
+            option {
+              value = "2000000"
+              +"2 Mhz"
+            }
+            option {
+              value = "5000000"
+              +"5 Mhz"
+            }
+            option {
+              value = "10000000"
+              +"10 Mhz"
+            }
+
+            onChangeFunction = {
+              val target = it.target as? HTMLSelectElement
+              target?.value?.toIntOrNull()?.let { speed ->
+                computer.speed = speed
+              }
+            }
+          }
+        }
+
+        // Buttons with fx-* attributes
+        button {
+          if (computer.getStatus() != MonTanaMiniComputer.ComputerStatus.EXECUTING) {
+            +"run"
+            onClickFunction = {
+              computer.run()
+              requestUpdate()
+            }
+          } else {
+            +"pause"
+            onClickFunction = {
+              computer.pause()
+              requestUpdate()
+            }
+          }
+        }
+        button {
+          disabled =
+            computer.getStatus() == MonTanaMiniComputer.ComputerStatus.WAITING && computer.rewindIndex >= 0
+
+          +"back"
+
+          onClickFunction = {
+            computer.back()
+            mainView.requestUpdate()
+            display.requestUpdate()
+          }
+        }
+        button {
+          +"step"
+
+          onClickFunction = {
+            computer.step()
+            mainView.requestUpdate()
+            display.requestUpdate()
+          }
+        }
+        button {
+          +"reset"
+
+          onClickFunction = {
+            computer.initMemory()
+            mainView.requestUpdate()
+            display.requestUpdate()
+          }
+        }
+      }
+    }
+  }
+
+}

src/jsMain/kotlin/mtmc/view/DisplayView.kt

@@ -0,0 +1,173 @@
+package mtmc.view
+
+import kotlinx.html.canvas
+import kotlinx.html.div
+import mtmc.display
+import mtmc.emulator.BufferedImageData
+import mtmc.emulator.BufferedImageDataWebGl
+import mtmc.emulator.MonTanaMiniComputer
+import nl.astraeus.komp.HtmlBuilder
+import nl.astraeus.komp.Komponent
+import nl.astraeus.komp.currentElement
+import org.khronos.webgl.Float32Array
+import org.khronos.webgl.WebGLBuffer
+import org.khronos.webgl.WebGLProgram
+import org.khronos.webgl.WebGLRenderingContext
+import org.khronos.webgl.WebGLShader
+import org.khronos.webgl.WebGLTexture
+import org.w3c.dom.HTMLCanvasElement
+
+// language=GLSL
+val vertexShader = """
+  attribute vec2 a_pos;
+  attribute vec2 a_uv;
+  varying vec2 v_uv;
+  void main() {
+    v_uv = a_uv;
+    gl_Position = vec4(a_pos, 0.0, 1.0);
+  }
+  """
+
+// language=GLSL
+val fragmentShader = """
+  precision mediump float;
+  varying vec2 v_uv;
+  uniform sampler2D u_tex;
+
+  void main() {
+    gl_FragColor = texture2D(u_tex, v_uv);
+  }
+""".trimIndent()
+
+typealias GL = WebGLRenderingContext
+
+class DiplayControlView(
+  val computer: MonTanaMiniComputer
+) : Komponent() {
+
+  override fun HtmlBuilder.render() {
+    div("display") {
+      include(display)
+    }
+  }
+}
+
+class DisplayView(
+  val computer: MonTanaMiniComputer
+) : Komponent() {
+  var ctx: WebGLRenderingContext? = null
+  var program: WebGLProgram? = null
+  var texture: WebGLTexture? = null
+  var buffer: WebGLBuffer? = null
+
+  override fun HtmlBuilder.render() {
+    canvas("display-canvas") {
+      width = "160px"
+      height = "144px"
+
+      val cv = currentElement() as? HTMLCanvasElement
+
+      ctx = cv?.getContext("webgl")?.unsafeCast<WebGLRenderingContext>()
+
+      if (program == null) {
+        createProgram()
+        createBuffer()
+        createTexture()
+      }
+    }
+  }
+
+  private fun createTexture() {
+    ctx?.let { gl: WebGLRenderingContext ->
+      texture = gl.createTexture()
+      gl.bindTexture(GL.TEXTURE_2D, texture)
+
+// Set texture parameters for pixel-perfect rendering
+      gl.texParameteri(GL.TEXTURE_2D, GL.TEXTURE_WRAP_S, GL.CLAMP_TO_EDGE)
+      gl.texParameteri(GL.TEXTURE_2D, GL.TEXTURE_WRAP_T, GL.CLAMP_TO_EDGE)
+      gl.texParameteri(GL.TEXTURE_2D, GL.TEXTURE_MIN_FILTER, GL.NEAREST)
+      gl.texParameteri(GL.TEXTURE_2D, GL.TEXTURE_MAG_FILTER, GL.NEAREST)
+    }
+  }
+
+  private fun createBuffer() {
+    ctx?.let { gl ->
+      // Create quad vertices
+      val vertices = Float32Array(
+        arrayOf(
+          -1f, -1f, 0f, 1f,  // position, texCoord
+          1f, -1f, 1f, 1f,
+          -1f, 1f, 0f, 0f,
+          1f, 1f, 1f, 0f
+        )
+      )
+
+      buffer = gl.createBuffer();
+      gl.bindBuffer(GL.ARRAY_BUFFER, buffer);
+      gl.bufferData(GL.ARRAY_BUFFER, vertices, GL.STATIC_DRAW);
+    }
+  }
+
+
+  private fun createProgram() {
+    val vs = createShader(WebGLRenderingContext.VERTEX_SHADER, vertexShader)
+    val fs = createShader(WebGLRenderingContext.FRAGMENT_SHADER, fragmentShader)
+    val prog = ctx?.createProgram()
+    if (vs != null && fs != null && prog != null) {
+      ctx?.attachShader(prog, vs)
+      ctx?.attachShader(prog, fs)
+      ctx?.linkProgram(prog)
+    }
+    program = prog
+  }
+
+  private fun createShader(type: Int, source: String): WebGLShader? {
+    var result: WebGLShader? = null
+    ctx?.let { gl ->
+      result = gl.createShader(type)
+      result?.let { shader ->
+        gl.shaderSource(shader, source)
+        gl.compileShader(shader)
+      }
+    }
+    return result
+  }
+
+  override fun renderUpdate() {
+    // move data to canvas
+    val buffer = computer.display.buffer
+    if (buffer is BufferedImageData) {
+      //ctx?.putImageData(buffer.imageData, 0.0, 0.0)
+    } else if (buffer is BufferedImageDataWebGl) {
+      ctx?.let { gl ->
+        gl.clear(GL.COLOR_BUFFER_BIT)
+
+        gl.useProgram(program)
+
+        val positionLocation = gl.getAttribLocation(program, "a_pos")
+        val texCoordLocation = gl.getAttribLocation(program, "a_uv")
+
+        gl.bindBuffer(GL.ARRAY_BUFFER, this.buffer)
+        gl.enableVertexAttribArray(positionLocation)
+        gl.vertexAttribPointer(positionLocation, 2, GL.FLOAT, false, 16, 0)
+        gl.enableVertexAttribArray(texCoordLocation)
+        gl.vertexAttribPointer(texCoordLocation, 2, GL.FLOAT, false, 16, 8)
+        gl.bindTexture(GL.TEXTURE_2D, texture);
+        gl.texImage2D(
+          GL.TEXTURE_2D,
+          0,              // level
+          GL.RGBA,         // internal format
+          buffer.width,
+          buffer.height,
+          0,              // border
+          GL.RGBA,         // format
+          GL.UNSIGNED_BYTE, // type
+          buffer.data // data
+        )
+
+        // Draw quad
+        gl.drawArrays(GL.TRIANGLE_STRIP, 0, 4);
+      }
+    }
+  }
+}

src/jsMain/kotlin/mtmc/view/MTMCView.kt

@@ -0,0 +1,34 @@
+package mtmc.view
+
+import kotlinx.html.div
+import mtmc.emulator.MonTanaMiniComputer
+import nl.astraeus.komp.HtmlBuilder
+import nl.astraeus.komp.Komponent
+
+class MTMCView(
+  val computer: MonTanaMiniComputer
+) : Komponent() {
+  val controlView = ControlView(computer)
+  val registerView = RegisterView(computer)
+  val memoryView = MemoryView(computer)
+  val displayView = DiplayControlView(computer)
+  val consoleView = ConsoleView(computer)
+
+  override fun HtmlBuilder.render() {
+    div("container") {
+      div("left-column") {
+        include(controlView)
+        include(registerView)
+        include(memoryView)
+      }
+      div("middle-column") {
+        include(displayView)
+        include(consoleView)
+      }
+      div("right-column") {
+        +"Files"
+      }
+    }
+  }
+
+}

src/jsMain/kotlin/mtmc/view/MemoryView.kt

@@ -0,0 +1,147 @@
+package mtmc.view
+
+import kotlinx.html.classes
+import kotlinx.html.div
+import kotlinx.html.table
+import kotlinx.html.td
+import kotlinx.html.title
+import kotlinx.html.tr
+import mtmc.asm.instructions.Instruction
+import mtmc.emulator.MonTanaMiniComputer
+import mtmc.emulator.Register
+import nl.astraeus.komp.HtmlBuilder
+import nl.astraeus.komp.Komponent
+
+fun ByteArray.asHex(address: Int): String {
+  val value = getShort(address)
+  return value.toHexString()
+}
+
+fun ByteArray.getShort(address: Int): Short {
+  val value = (this[address].toInt() and 0xff) * 256 + (this[address + 1].toInt() and 0xff)
+  return value.toShort()
+}
+
+
+enum class DisplayFormat {
+  DYN,
+  HEX,
+  DEC,
+  INS,
+  STR
+}
+
+private val ASCII_CODES = arrayOf<String>(
+  "NUL", "SOH", "STX", "ETX",
+  "EOT", "ENT", "ACK", "BEL",
+  "BS", "\\t", "\\n", "VT",
+  "\\f", "\\r", "SO", "SI",
+  "DLE", "DC1", "DC2", "DC3",
+  "DC4", "NAK", "SYN", "ETB",
+  "CAN", "EM", "SUB", "ESC",
+  "FS", "GS", "RS", "US",
+)
+
+class MemoryView(
+  val computer: MonTanaMiniComputer
+) : Komponent() {
+  var displayFormat: DisplayFormat = DisplayFormat.DYN
+
+  override fun HtmlBuilder.render() {
+    div("memory-panel") {
+      div("memory-header") {
+        +"Memory"
+      }
+      div("memory") {
+        table {
+          for (baseAddress in 0..<computer.memory.size step 16) {
+            tr {
+              var previousInstruction = 0x0fff.toShort()
+              for (offset in 0..<8) {
+                val address = baseAddress + offset * 2
+                val memoryClass = classFor(address)
+                val df = computeMemoryFormat(memoryClass)
+                val value = computer.memory.getShort(address)
+
+                td {
+                  when (memoryClass) {
+                    "curr" -> classes += "current-address"
+                    "code" -> classes += "code"
+                    "data" -> classes += "data"
+                    "heap" -> classes += "heap"
+                    "sta" -> classes += "stack"
+                  }
+
+                  title = address.toString() + " - " + value.toHexString()
+
+                  when (df) {
+                    DisplayFormat.DEC -> +value.toInt().toString()
+                    DisplayFormat.INS -> {
+                      +Instruction.disassemble(
+                        value,
+                        previousInstruction
+                      )
+                      previousInstruction = value
+                    }
+
+                    DisplayFormat.HEX -> +value.toHexString()
+                    DisplayFormat.STR -> +get1252String(value)
+                    else -> +"?"
+                  }
+                }
+              }
+            }
+          }
+        }
+      }
+    }
+  }
+
+  fun classFor(address: Int): String = if (address >= computer.getRegisterValue(Register.SP)) {
+    "sta"
+  } else if (address == computer.getRegisterValue(Register.PC).toInt()) {
+    "curr"
+  } else if (address <= computer.getRegisterValue(Register.CB)) {
+    "code"
+  } else if (address <= computer.getRegisterValue(Register.DB)) {
+    "data"
+  } else if (address <= computer.getRegisterValue(Register.BP)) {
+    "heap"
+  } else {
+    ""
+  }
+
+  private fun computeMemoryFormat(memoryClass: String?): DisplayFormat {
+    return if (displayFormat == DisplayFormat.DYN) {
+      when (memoryClass) {
+        "sta" -> DisplayFormat.DEC
+        "code", "curr" -> DisplayFormat.INS
+        "data", "heap" -> DisplayFormat.STR
+        else -> DisplayFormat.HEX
+      }
+    } else {
+      displayFormat
+    }
+  }
+
+
+  fun get1252String(value: Short): String {
+    val topByte = (value.toInt() ushr 8).toByte()
+    val bottomByte = value.toByte()
+
+    return if (topByte.toInt() != 0) {
+      get1252String(topByte) + " " + get1252String(
+        bottomByte
+      )
+    } else {
+      get1252String(bottomByte)
+    }
+  }
+
+  private fun get1252String(value: Byte): String = if (value in 0..<32) {
+    ASCII_CODES[value.toInt()]
+  } else {
+    "" + (value.toInt() and 0xff).toChar()
+  }
+
+}

src/jsMain/kotlin/mtmc/view/RegisterView.kt

@@ -0,0 +1,117 @@
+package mtmc.view
+
+import kotlinx.browser.document
+import kotlinx.dom.addClass
+import kotlinx.dom.removeClass
+import kotlinx.html.TABLE
+import kotlinx.html.classes
+import kotlinx.html.div
+import kotlinx.html.hr
+import kotlinx.html.id
+import kotlinx.html.span
+import kotlinx.html.table
+import kotlinx.html.td
+import kotlinx.html.tr
+import mtmc.emulator.MonTanaMiniComputer
+import mtmc.emulator.Register
+import nl.astraeus.komp.HtmlBuilder
+import nl.astraeus.komp.Komponent
+import org.w3c.dom.HTMLElement
+
+class RegisterView(
+  val computer: MonTanaMiniComputer
+) : Komponent() {
+
+  override fun HtmlBuilder.render() {
+    div {
+      table("register-table") {
+        for (index in 0..<16) {
+          showRegister(index)
+        }
+        tr {
+          td {
+            colSpan = "3"
+            hr {}
+          }
+        }
+        showRegister(16)
+        showRegister(17)
+        tr {
+          td("flags") {
+            colSpan = "3"
+            span {
+              +"flags t:"
+
+              div("blinken") {
+                id = "flags-t"
+                if (!computer.isFlagTestBitSet) {
+                  classes += "off"
+                }
+              }
+            }
+            span {
+              +"o:"
+              div("blinken") {
+                id = "flags-o"
+                classes += "off"
+              }
+            }
+            span {
+              +"e:"
+              div("blinken") {
+                id = "flags-e"
+                if (computer.getStatus() != MonTanaMiniComputer.ComputerStatus.PERMANENT_ERROR) {
+                  classes += "off"
+                }
+              }
+            }
+          }
+        }
+      }
+    }
+  }
+
+  override fun renderUpdate() {
+    for (register in 0..<18) {
+      val value = computer.registerFile[register]
+      for (bit in 15 downTo 0) {
+        val element = document.getElementById("bit-$bit-$register") as? HTMLElement ?: continue
+        if (value.toInt() and (1 shl bit) == 0) {
+          element.addClass("off")
+        } else {
+          element.removeClass("off")
+        }
+      }
+      val element = document.getElementById("register-$register") as? HTMLElement ?: continue
+      element.innerText = "${value.toInt() and 0xffff}"
+    }
+  }
+
+  private fun TABLE.showRegister(register: Int) {
+    val name = Register.fromInteger(register)
+    val value = computer.registerFile[register]
+    tr {
+      td {
+        +name
+      }
+      td("register-lights") {
+        for (bit in 15 downTo 0) {
+          div("blinken") {
+            id = "bit-$bit-$register"
+            if (value.toInt() and (1 shl bit) == 0) {
+              classes += "off"
+            }
+            if (bit % 4 == 0) {
+              classes += "space"
+            }
+          }
+        }
+      }
+      td("align-right") {
+        id = "register-$register"
+        +"${value.toInt() and 0xffff}"
+      }
+    }
+  }
+
+}

src/jsMain/resources/mtmc.css

@@ -0,0 +1,256 @@
+:root {
+    --pdp-blue: #243571;
+    --pdp-light-blue: #3286ce;
+    --pdp-beige: #fdfddc;
+    --pdp-white: #f1f1f6;
+    --pdp-off-white: #F0EBCD;
+    --filetree-gray: #666;
+}
+
+html, body {
+    padding: 0;
+    margin: 0;
+    box-sizing: border-box;
+}
+
+body {
+    overscroll-behavior: none;
+}
+
+.container {
+    display: grid;
+    grid-template-columns: 450px 450px 1fr;
+    grid-template-rows: 1fr;
+    overflow-y: auto;
+    gap: 5px;
+    background-color: var(--pdp-white);
+}
+
+.left-column {
+    grid-template-rows: auto auto minmax(0, 1fr);
+    display: grid;
+    grid-gap: 4px;
+    height: 100dvh;
+    max-height: 100dvh;
+    min-width: 450px;
+    max-width: 450px;
+}
+
+.middle-column {
+    background-color: #eee;
+    grid-template-rows: auto minmax(0, 1fr);
+    display: grid;
+    grid-gap: 4px;
+    height: 100dvh;
+    max-height: 100dvh;
+    min-width: 450px;
+    max-width: 450px;
+}
+
+.right-column {
+    background-color: #eee;
+    grid-template-rows: auto;
+    display: grid;
+    grid-gap: 4px;
+    height: 100dvh;
+    max-height: 100dvh;
+    min-width: 450px;
+}
+
+.align-right {
+    text-align: right;
+}
+
+/* control */
+
+.control-panel > * {
+    margin: 4px;
+}
+
+.control-header {
+    background-color: var(--pdp-blue);
+    color: var(--pdp-white);
+    font-family: monospace;
+    font-size: 32px;
+    padding: 4px 24px;
+    margin-left: 0;
+    margin-right: 0;
+}
+
+.control-header span {
+    display: inline-block;
+    margin-top: -6px;
+    margin-bottom: -6px;
+    padding: 4px 8px;
+    font-weight: bold;
+    font-size: 38px;
+    border-right: 4px solid white;
+    border-left: 4px solid white;
+}
+
+.control-header span:not(:first-child) {
+    border-left: none;
+}
+
+.control-secondary {
+    background-color: var(--pdp-light-blue);
+    color: var(--pdp-white);
+    font-family: monospace;
+    font-size: 18px;
+    font-style: italic;
+    text-align: center;
+    padding: 4px 4px;
+    margin-left: 0;
+    margin-right: 0;
+}
+
+.control-buttons {
+    text-align: right;
+}
+
+/* registers */
+
+table.register-table {
+    font-family: monospace;
+    width: 100%;
+    padding: 5px;
+    background-color: black;
+    color: white;
+    border-radius: 8px;
+}
+
+table.register-table tr td.align-right {
+    text-align: right;
+    min-width: 100px;
+}
+
+table.register-table tr td.register-lights {
+    padding-left: 20px;
+}
+
+table.register-table tr td.flags {
+    text-align: center;
+}
+
+table.register-table tr td.flags span {
+    margin-left: 8px;
+}
+
+table.register-table tr td.flags span .blinken {
+    margin-left: 4px;
+    top: 2px;
+    position: relative;
+}
+
+.blinken {
+    display: inline-block;
+    margin-right: 2px;
+    height: 6px;
+    width: 6px;
+    border-radius: 6px;
+    padding: 3px;
+    background-color: red;
+}
+
+.blinken.off {
+    background-color: #5c0119;
+}
+
+.blinken.space {
+    margin-right: 8px;
+}
+
+/* memory */
+
+.memory-panel {
+    background-color: #eee;
+    display: flex;
+    flex-direction: column;
+}
+
+.memory-header {
+    font-family: monospace;
+    font-weight: bold;
+    font-size: 16px;
+    /* overflow: auto; */
+    padding: 4px;
+}
+
+.memory {
+    overflow: auto;
+}
+
+.memory table tr td {
+    font-family: monospace;
+    font-size: 8px;
+}
+
+.current-address {
+    background-color: #78e878;
+}
+
+.code {
+    background-color: darkseagreen;
+}
+
+.data {
+    background-color: lightgoldenrodyellow;
+}
+
+.heap {
+    background-color: lightcoral;
+}
+
+.stack {
+    background-color: lightsalmon;
+}
+
+/* display */
+
+.display {
+    min-height: 480px;
+}
+
+.display-canvas {
+    padding: 24px 64px;
+    width: 320px;
+    height: 288px;
+    image-rendering: pixelated; /* Keeps sharp pixels, no smoothing */
+    image-rendering: -moz-crisp-edges; /* Firefox */
+    image-rendering: crisp-edges; /* Standard */
+}
+/* console */
+
+.console {
+    color: #ffcc00;
+    background-color: #35291c;
+    white-space: pre-wrap;
+    font-family: monospace;
+    font-weight: bold;
+    padding: 5px;
+    overflow: auto;
+}
+
+.console-prompt {
+    margin-right: 6px;
+}
+
+input.console-input {
+    color: #ffcc00;
+    background-color: #35291c;
+    border: none;
+    outline: none;
+    font-weight: bold;
+    font-family: monospace;
+}
+
+.small-button {
+    transform: rotate(-25deg) translateY(20px) translateX(-20px);
+    margin: 2px;
+    width: 50px;
+    background-color: #7e777b;
+    border: 1px solid dimgray;
+    border-radius: 8px;
+    color: whitesmoke;
+    box-shadow: rgb(0, 0, 0, .2) 2px 2px 1px 1px;
+}

src/jvmMain/kotlin/mtmc/Main.kt

@@ -7,9 +7,9 @@ import io.undertow.predicate.Predicates
 import io.undertow.server.handlers.encoding.ContentEncodingRepository
 import io.undertow.server.handlers.encoding.EncodingHandler
 import io.undertow.server.handlers.encoding.GzipEncodingProvider
-import nl.astraeus.logger.Logger
 import mtmc.db.Database
 import mtmc.web.RequestHandler
+import nl.astraeus.logger.Logger
 
 val log = Logger()
 
@@ -58,7 +58,6 @@ fun main() {
     .setServerOption(UndertowOptions.SHUTDOWN_TIMEOUT, 1000)
     .build()
 
-  println("Starting undertow server at port 6007...")
+  println("Starting undertow server at port $SERVER_PORT...")
   server?.start()
-
 }

src/jvmMain/kotlin/mtmc/emulator/BufferedImage.jvm.kt

@@ -0,0 +1,13 @@
+package mtmc.emulator
+
+actual fun createBufferedImage(width: Int, height: Int): BufferedImage {
+  TODO("Not yet implemented")
+}
+
+actual fun createCanvasImage(width: Int, height: Int): BufferedImage {
+  TODO("Not yet implemented")
+}
+
+actual fun createGLImage(width: Int, height: Int): BufferedImage {
+  TODO("Not yet implemented")
+}

src/jvmMain/kotlin/mtmc/util/PlatformSpecific.jvm.kt

@@ -1,3 +1,12 @@
 package mtmc.util
 
-actual fun currentTimeMillis(): Long = System.currentTimeMillis()
+actual fun currentTimeMillis(): Double = System.currentTimeMillis().toDouble()
+actual fun requestAnimationFrame(action: (Double) -> Unit) {
+  error("requestAnimationFrame is not supported on JVM")
+}
+
+actual fun immediateTimeout(action: (Double) -> Unit): Int = 0
+
+actual fun time(): Double = System.nanoTime() * 1000.0
+
+actual fun setTimeout(action: () -> Unit) {}

src/jvmMain/kotlin/mtmc/web/Index.kt

@@ -3,6 +3,7 @@ package mtmc.web
 import kotlinx.html.body
 import kotlinx.html.head
 import kotlinx.html.html
+import kotlinx.html.link
 import kotlinx.html.meta
 import kotlinx.html.script
 import kotlinx.html.stream.appendHTML
@@ -18,7 +19,7 @@ fun generateIndex(patch: String?): String {
     result.appendHTML(true).html {
       head {
         title(pageTitle)
-        //link("/css/all.min.css", "stylesheet")
+        link("/mtmc.css", "stylesheet")
       }
       body {
         script(src = "/$repoName.js") {}

src/jvmMain/kotlin/mtmc/web/RequestHandler.kt

@@ -5,12 +5,13 @@ import io.undertow.server.HttpServerExchange
 import io.undertow.server.handlers.PathHandler
 import io.undertow.server.handlers.resource.PathResourceManager
 import io.undertow.server.handlers.resource.ResourceHandler
+import io.undertow.util.Headers
 import mtmc.itemUrl
 import java.nio.file.Paths
-import kotlin.text.startsWith
 
 object IndexHandler : HttpHandler {
   override fun handleRequest(exchange: HttpServerExchange) {
+    exchange.responseHeaders.put(Headers.CONTENT_TYPE, "text/html")
     if (exchange.requestPath.startsWith("/$itemUrl/")) {
       exchange.responseSender.send(generateIndex(null))
     } else {