From 14f3667e7e27d9ae73eeff57224830fed7345980 Mon Sep 17 00:00:00 2001
From: Steven Hugg <hugg@fasterlight.com>
Date: Mon, 2 Jan 2017 20:42:15 -0500
Subject: [PATCH] started on asteroids vector driver

---
 doc/notes.txt            |   1 +
 index.html               |  22 +--
 src/emu.js               | 198 +++++++++++++++++++++++
 src/platform/apple2.js   | 235 +++++++++++++++++++++++++++
 src/platform/atarivec.js | 334 +++++++++++++++++++++++++++++++++++++++
 src/platform/vcs.js      |  12 +-
 src/ui.js                |  40 +++--
 src/util.js              | 207 ++++++++++++++++++++++++
 8 files changed, 1022 insertions(+), 27 deletions(-)
 create mode 100644 src/emu.js
 create mode 100644 src/platform/apple2.js
 create mode 100644 src/platform/atarivec.js
 create mode 100644 src/util.js

diff --git a/doc/notes.txt b/doc/notes.txt
index 411cee67..26651923 100644
--- a/doc/notes.txt
+++ b/doc/notes.txt
@@ -22,3 +22,4 @@ TODO:
 - break on BRK/illegal opcode?
 - start analysis from vector address
 
+cat ~/Downloads/appleiigo.rom | hexdump -v -e '"\n" 32/1 "%u,"' ; echo
diff --git a/index.html b/index.html
index 85af5fda..d15854b9 100644
--- a/index.html
+++ b/index.html
@@ -25,12 +25,12 @@ body {
 .gutter-info {
   width: 1em;
 }
-.tooltip {
+.tooltipbox {
     position: relative;
     display: inline-block;
     border-bottom: 1px dotted black;
 }
-.tooltip .tooltiptext {
+.tooltipbox .tooltiptext {
     visibility: hidden;
     width: 120px;
     background-color: black;
@@ -43,7 +43,7 @@ body {
     position: absolute;
     z-index: 10;
 }
-.tooltip:hover .tooltiptext {
+.tooltipbox:hover .tooltiptext {
     visibility: visible;
 }
 #notebook {
@@ -57,7 +57,7 @@ div.editor {
   bottom:0;
   right:0;
   width:50%;
-  height:100vh;
+  height:120vh;
   background-color:#999;
   line-height:1.25;
   font-size:12pt;
@@ -67,16 +67,17 @@ div.emulator {
   left:50%;
   top:0;
   width:50%;
-  height:100vh;
+  height:120vh;
   overflow-y: scroll;
   background-color: #666;
+  margin-top: 20px auto 0;
 }
 div.mem_info {
-  position: absolute;
+  position: fixed;
+  left: 51%;
   bottom: 10px;
   background-color: #333;
   color: #66ff66;
-  left: 20px;
   white-space: pre;
   padding: 20px;
   z-index: 2;
@@ -144,7 +145,7 @@ a.dropdown-toggle {
       <span class="dbg_info" id="dbg_info"></span>
     </div>
   </div>
-  <div style="margin-top: 30px auto 0; min-height: 594px;" class="emulator" id="emulator">
+  <div class="emulator" id="emulator">
     <div id="javatari-screen" style="margin: 0 auto; box-shadow: 2px 2px 10px rgb(60, 60, 60);"></div>
     <div id="javatari-console-panel" style="margin: 0 auto; box-shadow: 2px 2px 10px rgb(60, 60, 60);"></div>
     <div id="mem_info" class="mem_info" style="display:none">
@@ -186,8 +187,11 @@ a.dropdown-toggle {
 <link rel="stylesheet" href="codemirror/addon/dialog/dialog.css">
 
 <script src="javatari.js/release/javatari/javatari.js"></script>
+<script src="src/emu.js"></script>
 <script src="src/platform/vcs.js"></script>
-
+<script src="src/platform/apple2.js"></script>
+<script src="src/platform/atarivec.js"></script>
+<script src="local/vecrom.js"></script>
 <script src="src/ui.js"></script>
 
 </body>
diff --git a/src/emu.js b/src/emu.js
new file mode 100644
index 00000000..7fad53ee
--- /dev/null
+++ b/src/emu.js
@@ -0,0 +1,198 @@
+
+// Emulator classes
+
+RasterVideo = function(mainElement, width, height, options) {
+  var self = this;
+  var canvas, ctx;
+  var imageData, buf8, datau32;
+
+  this.start = function() {
+    // TODO
+    fsElement = document.createElement('div');
+    fsElement.style.position = "relative";
+    fsElement.style.padding = "50px";
+    //fsElement.style.width = "100%";
+    //fsElement.style.height = "100%";
+    fsElement.style.overflow = "hidden";
+    fsElement.style.background = "black";
+
+    canvas = document.createElement('canvas');
+    canvas.width = width;
+    canvas.height = height;
+
+    fsElement.appendChild(canvas);
+    mainElement.appendChild(fsElement);
+
+    ctx = canvas.getContext('2d');
+    imageData = ctx.createImageData(width, height);
+    var buf = new ArrayBuffer(imageData.data.length);
+    buf8 = new Uint8ClampedArray(buf);
+    datau32 = new Uint32Array(buf);
+  }
+
+  this.getFrameData = function() {
+    return datau32;
+  }
+
+  this.updateFrame = function() {
+    imageData.data.set(buf8);
+    ctx.putImageData(imageData, 0, 0);
+  }
+
+/*
+mainElement.style.position = "relative";
+mainElement.style.overflow = "hidden";
+mainElement.style.outline = "none";
+mainElement.tabIndex = "-1";               // Make it focusable
+
+borderElement = document.createElement('div');
+borderElement.style.position = "relative";
+borderElement.style.overflow = "hidden";
+borderElement.style.background = "black";
+borderElement.style.border = "0 solid black";
+borderElement.style.borderWidth = "" + borderTop + "px " + borderLateral + "px " + borderBottom + "px";
+if (Javatari.SCREEN_CONTROL_BAR === 2) {
+    borderElement.style.borderImage = "url(" + IMAGE_PATH + "screenborder.png) " +
+        borderTop + " " + borderLateral + " " + borderBottom + " repeat stretch";
+}
+
+fsElement = document.createElement('div');
+fsElement.style.position = "relative";
+fsElement.style.width = "100%";
+fsElement.style.height = "100%";
+fsElement.style.overflow = "hidden";
+fsElement.style.background = "black";
+
+document.addEventListener("fullscreenchange", fullScreenChanged);
+document.addEventListener("webkitfullscreenchange", fullScreenChanged);
+document.addEventListener("mozfullscreenchange", fullScreenChanged);
+document.addEventListener("msfullscreenchange", fullScreenChanged);
+
+borderElement.appendChild(fsElement);
+
+canvas.style.position = "absolute";
+canvas.style.display = "block";
+canvas.style.left = canvas.style.right = 0;
+canvas.style.top = canvas.style.bottom = 0;
+canvas.style.margin = "auto";
+canvas.tabIndex = "-1";               // Make it focusable
+canvas.style.outline = "none";
+fsElement.appendChild(canvas);
+
+setElementsSizes(jt.CanvasDisplay.DEFAULT_STARTING_WIDTH, jt.CanvasDisplay.DEFAULT_STARTING_HEIGHT);
+
+mainElement.appendChild(borderElement);
+*/
+}
+
+VectorVideo = function(mainElement, width, height) {
+  var self = this;
+  var canvas, ctx;
+  var persistenceAlpha = 0.5;
+  var jitter = 1.0;
+
+  this.start = function() {
+    // TODO
+    var fsElement = document.createElement('div');
+    fsElement.style.position = "relative";
+    fsElement.style.padding = "20px";
+    fsElement.style.overflow = "hidden";
+    fsElement.style.background = "black";
+
+    canvas = document.createElement('canvas');
+    canvas.width = width;
+    canvas.height = height;
+    canvas.style.width = "100%";
+    canvas.style.height = "100%";
+    canvas.tabIndex = "-1";               // Make it focusable
+
+    fsElement.appendChild(canvas);
+    mainElement.appendChild(fsElement);
+
+    ctx = canvas.getContext('2d');
+  }
+
+  this.setKeyboardEvents = function(callback) {
+    canvas.onkeydown = function(e) {
+      callback(e.key, 1);
+    };
+    canvas.onkeyup = function(e) {
+      callback(e.key, 0);
+    };
+  }
+
+  this.clear = function() {
+    ctx.globalCompositeOperation = 'source-over';
+    ctx.globalAlpha = persistenceAlpha;
+    ctx.fillStyle = '#000000';
+    ctx.fillRect(0, 0, width, height);
+    ctx.globalAlpha = 1.0;
+    ctx.globalCompositeOperation = 'lighter';
+  }
+
+  this.drawLine = function(x1, y1, x2, y2, intensity) {
+    //console.log(x1, y1, x2, y2, intensity);
+    if (intensity > 0) {
+      // TODO: landscape vs portrait
+      ctx.beginPath();
+      // TODO: dots
+      var jx = jitter * (Math.random() - 0.5);
+      var jy = jitter * (Math.random() - 0.5);
+      x1 += jx;
+      x2 += jx;
+      y1 += jy;
+      y2 += jy;
+      ctx.moveTo(x1, height-y1);
+      ctx.lineTo(x2+1, height-y2);
+      ctx.strokeStyle = '#ffffff';
+      ctx.lineWidth = intensity*0.1;
+      ctx.stroke();
+    }
+  }
+}
+
+SampleAudio = function(clockfreq) {
+
+}
+
+RAM = function(size) {
+  var memArray = new ArrayBuffer(size);
+  this.mem = new Uint8Array(memArray);
+}
+
+// TODO
+AnimationTimer = function(frequencyHz, callback) {
+  var intervalMsec = 1000.0 / frequencyHz;
+  var curTime = 0;
+  var running;
+  var useReqAnimFrame = false; // TODO: disable on OS X
+
+  function scheduleFrame() {
+    if (useReqAnimFrame)
+      window.requestAnimationFrame(nextFrame);
+    else
+      setTimeout(nextFrame, intervalMsec);
+  }
+
+  var nextFrame = function(timestamp) {
+    // TODO: calculate framerate
+    callback();
+    if (running) {
+      scheduleFrame();
+    }
+  }
+  this.isRunning = function() {
+    return running;
+  }
+  this.start = function() {
+    if (!running) {
+      running = true;
+      scheduleFrame();
+    }
+  }
+  this.stop = function() {
+    running = false;
+  }
+}
+
+//
diff --git a/src/platform/apple2.js b/src/platform/apple2.js
new file mode 100644
index 00000000..29c575d8
--- /dev/null
+++ b/src/platform/apple2.js
@@ -0,0 +1,235 @@
+
+var PRESETS = [
+]
+
+Apple2Platform = function(mainElement) {
+  var self = this;
+  var cpuFrequency = 1.023;
+  var cpuCyclesPerLine = 65;
+  var cpu, ram, rom, bus;
+  var video, audio, timer;
+
+  this.start = function() {
+    cpu = new jt.M6502();
+    ram = new RAM(0xc000);
+    //rom = new lzgmini().decode(APPLEIIGO_LZG).slice(0,12288);
+    // bus
+    bus = {
+      read: function(address) {
+        if (address >= 0xd000 && address <= 0xffff) {
+          return rom[address - 0xd000];
+        } else if (address < 0xc000) {
+          return ram.mem[address];
+        }
+      },
+      write: function(address, val) {
+        if (address < 0xc000) {
+          ram.mem[address] = val;
+        }
+      }
+    };
+    cpu.connectBus(bus);
+    // create video/audio
+    video = new RasterVideo(mainElement,280,192);
+    audio = new SampleAudio(cpuFrequency);
+    video.start();
+    var idata = video.getFrameData();
+    var colors = [0xffff0000, 0xff00ff00];
+    timer = new AnimationTimer(60, function() {
+      // 262.5 scanlines per frame
+      var iaddr = 0x2000;
+      var iofs = 0;
+      breakClock = -1;
+      clock = 0;
+      for (var sl=0; sl<262; sl++) {
+        for (var i=0; i<cpuCyclesPerLine; i++) {
+          if (debugCondition && breakClock < 0 && debugCondition()) { breakClock = clock; }
+          clock++;
+          cpu.clockPulse();
+          // TODO: audio
+        }
+        if (sl < 192) {
+          for (var xo=0; xo<35; xo++) {
+            var b = ram.mem[iaddr++];
+            idata[iofs++] = colors[(b>>0)&1];
+            idata[iofs++] = colors[(b>>1)&1];
+            idata[iofs++] = colors[(b>>2)&1];
+            idata[iofs++] = colors[(b>>3)&1];
+            idata[iofs++] = colors[(b>>4)&1];
+            idata[iofs++] = colors[(b>>5)&1];
+            idata[iofs++] = colors[(b>>6)&1];
+          }
+        }
+      }
+      video.updateFrame();
+    });
+  }
+
+  this.getOpcodeMetadata = function(opcode, offset) {
+    return Javatari.getOpcodeMetadata(opcode, offset); // TODO
+  }
+
+  this.loadROM = function(title, data) {
+    if(data.length != 0x3000) {
+      throw "ROM length must be == 0x3000";
+    }
+    rom = data;
+    this.reset();
+  }
+
+  this.getRasterPosition = function() {
+    return {x:xpos, y:ypos};
+  }
+
+  this.isRunning = function() {
+    return timer.isRunning();
+  }
+  this.pause = function() {
+    timer.stop();
+  }
+  this.resume = function() {
+    timer.start();
+  }
+  this.reset = function() {
+    cpu.reset();
+  }
+  this.getOriginPC = function() {
+    return (this.readAddress(0xfffc) | (this.readAddress(0xfffd) << 8)) & 0xffff;
+  }
+  this.readAddress = function(addr) {
+    return bus.read(addr);
+  }
+
+  var onBreakpointHit;
+  var debugCondition;
+  var debugSavedState = null;
+  var debugBreakState = null;
+  var debugTargetClock = 0;
+  var debugClock = 0;
+  var debugFrameStartClock = 0;
+  var breakClock;
+
+  this.setDebugCondition = function(debugCond) {
+    if (debugSavedState) {
+      self.loadState(debugSavedState);
+    } else {
+      debugSavedState = self.saveState();
+    }
+    debugClock = 0;
+    debugCondition = debugCond;
+    self.resume();
+  }
+  this.setupDebug = function(callback) {
+    onBreakpointHit = callback;
+  }
+  this.clearDebug = function() {
+    debugSavedState = null;
+    debugTargetClock = 0;
+    debugClock = 0;
+    debugFrameStartClock = 0;
+    onBreakpointHit = null;
+    debugCondition = null;
+  }
+  this.breakpointHit = function() {
+    debugBreakState = self.saveState();
+    console.log("Breakpoint at clk", debugClock, "PC", debugBreakState.c.PC.toString(16));
+    this.pause();
+    if (onBreakpointHit) {
+      onBreakpointHit(debugBreakState);
+    }
+  }
+  this.step = function() {
+    var previousPC = -1;
+    self.setDebugCondition(function() {
+      if (debugClock++ >= debugTargetClock) {
+        var thisState = cpu.saveState();
+        if (previousPC < 0) {
+          previousPC = thisState.PC;
+        } else {
+          if (thisState.PC != previousPC && thisState.T == 0) {
+            //console.log(previousPC.toString(16), thisPC.toString(16));
+            debugTargetClock = debugClock-1;
+            self.breakpointHit();
+            return true;
+          }
+        }
+      }
+      return false;
+    });
+  }
+  this.runToPC = function(targetPC) {
+    var self = this;
+    self.setDebugCondition(function() {
+      if (debugClock++ >= debugTargetClock) {
+        var thisPC = cpu.saveState().PC;
+        if (thisPC == targetPC) {
+          self.breakpointHit();
+          debugTargetClock = debugClock;
+          return true;
+        } else {
+          return false;
+        }
+      }
+    });
+  }
+
+  this.loadState = function(state) {
+    cpu.loadState(state.c);
+    ram.mem.set(state.b);
+  }
+  this.saveState = function() {
+    return {
+      c:cpu.saveState(),
+      b:ram.mem.slice(0),
+    };
+  }
+};
+
+APPLEIIGO_LZG = [
+  76,90,71,0,0,48,0,0,0,5,159,47,60,46,159,1,21,25,30,52,65,80,80,76,69,73,73,71,79,32,82,79,
+  77,49,46,48,0,52,31,52,31,52,31,52,31,52,31,52,31,52,31,52,31,52,28,52,6,32,0,224,25,30,67,52,
+  30,52,28,25,31,174,52,31,52,30,52,28,52,6,25,63,107,52,31,52,30,52,28,25,63,101,52,19,25,31,139,52,
+  31,52,31,52,31,52,31,52,31,52,31,52,31,52,31,52,31,52,31,52,31,52,31,52,25,160,32,52,28,32,32,160,
+  25,14,40,1,16,16,12,5,19,15,6,20,32,14,15,20,32,1,22,1,9,12,1,2,12,5,25,16,40,198,207,210,
+  160,205,207,210,197,160,201,206,30,3,205,193,212,201,207,206,160,208,204,197,193,211,197,160,195,204,201,195,203,160,30,8,
+  160,25,8,40,212,200,197,160,193,208,30,25,201,201,199,207,160,204,207,52,129,194,197,204,207,215,30,28,52,10,25,29,
+  224,52,22,76,3,224,32,88,252,162,39,189,0,223,157,128,4,202,16,247,30,3,48,223,157,0,5,30,195,30,78,25,
+  5,3,96,30,3,6,30,195,144,30,25,7,30,3,76,64,224,52,65,25,30,131,52,31,52,31,52,31,52,31,52,31,
+  52,31,52,31,52,31,52,31,52,31,52,31,52,31,52,31,52,31,52,31,52,31,52,31,52,31,52,31,52,31,52,31,
+  52,31,52,24,201,206,176,238,201,201,144,234,201,204,240,230,208,232,234,52,11,72,74,41,3,9,4,133,41,104,41,24,
+  144,2,105,127,133,40,10,10,5,40,133,40,96,25,30,116,0,165,37,32,193,251,101,32,25,29,75,52,21,165,34,72,
+  32,36,252,165,40,133,42,165,41,133,43,164,33,136,104,105,1,197,35,176,13,30,78,177,40,145,42,136,16,249,48,225,
+  160,0,32,158,252,176,134,164,36,169,160,145,40,200,196,33,144,249,25,30,199,52,27,164,36,177,40,72,41,63,9,64,
+  145,40,104,108,56,25,19,27,32,12,253,32,165,251,52,161,201,155,240,243,25,28,141,52,6,32,142,253,165,51,32,237,
+  253,162,1,138,240,243,202,32,53,253,201,149,208,2,177,40,201,224,144,2,41,223,157,0,2,201,141,208,178,32,156,252,
+  169,141,208,91,164,61,166,60,30,39,32,64,249,160,0,169,173,76,237,253,25,28,87,52,31,52,31,52,31,52,31,52,
+  31,52,31,52,31,52,31,52,31,52,31,52,31,52,31,52,28,52,7,169,0,133,28,165,230,133,27,160,0,132,26,165,
+  28,145,26,32,126,244,200,208,246,230,27,165,27,41,31,208,238,96,133,226,134,224,132,225,72,41,192,133,38,74,74,5,
+  38,133,38,104,133,39,10,10,10,38,39,52,66,102,38,165,39,41,31,5,230,133,39,138,192,0,240,5,160,35,105,4,
+  200,233,7,176,251,132,229,170,189,185,244,133,48,152,74,165,228,133,28,176,21,28,0,35,52,4,10,201,192,16,6,165,
+  28,73,127,133,28,25,254,218,52,31,52,31,52,31,52,31,52,31,52,31,52,28,52,10,74,8,32,71,248,40,169,15,
+  144,2,105,224,133,46,177,38,69,48,37,46,81,38,145,38,96,32,0,248,196,44,176,17,200,32,14,248,144,246,105,1,
+  72,30,8,104,197,45,144,245,96,160,47,208,2,160,39,132,45,160,39,169,0,133,48,32,40,248,136,16,246,96,21,5,
+  4,126,39,21,6,4,126,38,10,10,25,130,52,96,165,48,24,105,3,41,15,133,48,10,52,1,5,48,133,48,25,103,
+  223,144,4,74,52,1,41,15,25,107,240,168,74,144,9,106,176,16,201,162,240,12,41,135,74,170,189,98,249,32,121,248,
+  208,4,160,128,169,0,170,189,166,249,133,46,41,3,133,47,152,41,143,170,152,160,3,224,138,240,11,74,144,8,74,74,
+  9,32,136,208,250,200,136,208,242,25,159,59,52,31,52,31,52,20,216,32,132,254,32,47,251,32,147,254,32,137,254,173,
+  88,192,173,90,192,173,93,192,173,95,192,173,255,207,44,16,192,216,32,58,255,32,96,251,169,0,133,0,169,198,133,1,
+  108,25,30,111,52,29,21,3,19,108,221,219,199,207,25,10,13,173,112,192,160,0,234,234,189,100,192,16,4,200,208,248,
+  136,96,169,0,133,72,173,86,192,173,84,192,173,81,192,169,0,240,11,173,80,192,173,83,192,32,54,248,169,20,133,34,
+  30,22,32,169,40,133,33,169,24,133,35,169,23,133,37,76,34,252,32,88,252,160,9,185,8,251,153,14,4,136,208,247,
+  96,173,243,3,73,165,141,244,3,96,201,141,208,24,172,0,192,16,19,192,147,208,15,44,16,192,30,68,251,192,131,240,
+  3,30,4,76,253,251,25,12,148,21,29,7,248,40,133,40,96,201,135,208,18,169,64,32,168,252,160,192,169,12,52,193,
+  173,48,192,136,208,245,96,164,36,145,40,230,36,165,36,197,33,176,102,96,201,160,176,239,168,16,236,201,141,240,90,201,
+  138,52,97,136,208,201,198,36,16,232,165,33,133,36,198,36,165,34,197,37,176,11,198,37,21,28,7,248,0,72,32,36,
+  252,32,158,252,160,0,104,105,0,197,35,144,240,176,202,165,34,133,37,160,0,132,36,240,228,169,0,133,36,230,30,62,
+  30,16,182,198,37,21,29,7,248,21,6,7,248,56,72,233,1,208,252,104,52,129,246,96,230,66,208,2,230,67,165,60,
+  197,62,165,61,229,63,230,60,30,6,61,25,125,244,52,18,21,13,7,248,230,78,208,2,230,79,44,0,192,16,245,145,
+  40,173,0,192,44,16,192,96,21,10,7,248,254,96,165,50,72,169,255,133,50,189,0,2,32,237,253,104,30,129,201,136,
+  240,29,201,152,240,10,224,248,144,3,32,58,255,232,208,19,169,220,30,21,21,10,7,248,254,21,30,7,248,52,27,0,
+  72,25,162,88,32,229,253,104,41,15,9,176,201,186,144,2,105,6,108,54,0,201,160,144,2,37,50,132,53,72,32,120,
+  251,104,164,53,25,49,47,64,25,10,5,25,11,24,177,60,145,66,32,180,252,144,247,25,190,97,52,1,160,63,208,2,
+  160,255,132,50,25,98,82,62,162,56,160,27,208,8,30,130,54,160,240,165,62,41,15,240,6,9,192,160,0,240,2,169,
+  253,148,0,149,1,96,234,234,76,21,31,30,67,52,7,169,135,76,237,253,165,72,72,165,69,166,70,164,71,25,110,22,
+  25,62,27,52,30,52,14,245,3,251,3,98,250,98,250
+];
diff --git a/src/platform/atarivec.js b/src/platform/atarivec.js
new file mode 100644
index 00000000..7729b366
--- /dev/null
+++ b/src/platform/atarivec.js
@@ -0,0 +1,334 @@
+
+var PRESETS = [
+]
+
+AtariVectorPlatform = function(mainElement) {
+  var self = this;
+  var cpuFrequency = 1500000.0;
+  var cpuCyclesPerNMI = 6000;
+  var cpuCyclesPerFrame = Math.round(cpuFrequency/60);
+  var cpu, cpuram, dvgram, rom, vecrom, bus, dvg;
+  var video, audio, timer;
+  var clock;
+  var switches = new RAM(16).mem;
+  var nmicount = cpuCyclesPerNMI;
+
+  this.start = function() {
+    cpu = new jt.M6502();
+    cpuram = new RAM(0x400);
+    dvgram = new RAM(0x2000);
+    vecrom = VECROM;
+    //switches[5] = 0xff;
+    //switches[7] = 0xff;
+    // bus
+    bus = {
+      read: function(address) {
+        address &= 0x7fff;
+        if (address >= 0x6800 && address <= 0x7fff) {
+          return rom[address - 0x6800];
+        } else if (address <= 0x3ff) {
+          return cpuram.mem[address];
+        } else if (address >= 0x5000 && address <= 0x5fff) {
+          return vecrom[address - 0x5000];
+        } else if (address >= 0x4000 && address <= 0x5fff) {
+          return dvgram.mem[address - 0x4000];
+        } else if (address >= 0x2000 && address <= 0x3fff) {
+          if (address == 0x2001)
+            return ((clock/500) & 1) ? 0xff : 0x00;
+          else if (address >= 0x2000 && address <= 0x2007)
+            return switches[address - 0x2000];
+          else if (address >= 0x2400 && address <= 0x2407)
+            return switches[address - 0x2400 + 8];
+        }
+        return 0xff;
+      },
+      write: function(address, val) {
+        address &= 0x7fff;
+        if (address < 0x3ff) {
+          cpuram.mem[address] = val;
+        } else if (address >= 0x4000 && address <= 0x5fff) {
+          dvgram.mem[address - 0x4000] = val;
+        } else if (address >= 0x3000 && address <= 0x3fff) {
+          //console.log(address.toString(16), val);
+          if (address == 0x3000) dvg.runUntilHalt();
+          // TODO: draw asynchronous or allow poll of HALT ($2002)
+        }
+      }
+    };
+    cpu.connectBus(bus);
+    // create video/audio
+    video = new VectorVideo(mainElement,1024,1024);
+    dvg = new DVGStateMachine(bus, video);
+    audio = new SampleAudio(cpuFrequency);
+    video.start();
+    timer = new AnimationTimer(60, function() {
+      video.clear();
+      // 262.5 scanlines per frame
+      var iaddr = 0x4000;
+      var iofs = 0;
+      breakClock = -1;
+      clock = 0;
+      for (var i=0; i<cpuCyclesPerFrame; i++) {
+        if (debugCondition && breakClock < 0 && debugCondition()) { breakClock = clock; }
+        clock++;
+        if (--nmicount == 0)  {
+          //console.log("NMI", cpu.saveState());
+          var n = cpu.setNMIAndWait();
+          clock += n;
+          nmicount = cpuCyclesPerNMI - n;
+          //console.log(n, clock, nmicount);
+        }
+        cpu.clockPulse();
+      }
+    });
+    video.setKeyboardEvents(function(key,flags) {
+      var KEY2ADDR = {
+        "Shift": 3,
+        " ": 4,
+        "5": 8+0,
+        "6": 8+1,
+        "7": 8+2,
+        "1": 8+3,
+        "2": 8+4,
+        ArrowUp: 8+5,
+        ArrowRight: 8+6,
+        ArrowLeft: 8+7,
+      };
+      var addr = KEY2ADDR[key];
+      console.log(key,flags,addr);
+      if (addr >= 0) {
+        switches[addr] = (flags&1) ? 0xff : 0x00;
+      }
+    });
+  }
+
+  this.getOpcodeMetadata = function(opcode, offset) {
+    return Javatari.getOpcodeMetadata(opcode, offset); // TODO
+  }
+
+  this.loadROM = function(title, data) {
+    if(data.length != 0x1800) {
+      throw "ROM length must be == 0x1800";
+    }
+    rom = data;
+    this.reset();
+  }
+
+  this.getRasterPosition = function() {
+    return {x:0, y:0};
+  }
+
+  this.isRunning = function() {
+    return timer.isRunning();
+  }
+  this.pause = function() {
+    timer.stop();
+  }
+  this.resume = function() {
+    timer.start();
+  }
+  this.reset = function() {
+    this.clearDebug();
+    cpu.reset();
+  }
+  this.getOriginPC = function() {
+    return (this.readAddress(0xfffc) | (this.readAddress(0xfffd) << 8)) & 0xffff;
+  }
+  this.readAddress = function(addr) {
+    return bus.read(addr);
+  }
+
+  var onBreakpointHit;
+  var debugCondition;
+  var debugSavedState = null;
+  var debugBreakState = null;
+  var debugTargetClock = 0;
+  var debugClock = 0;
+  var debugFrameStartClock = 0;
+  var breakClock;
+
+  this.setDebugCondition = function(debugCond) {
+    if (debugSavedState) {
+      self.loadState(debugSavedState);
+    } else {
+      debugSavedState = self.saveState();
+    }
+    debugClock = 0;
+    debugCondition = debugCond;
+    self.resume();
+  }
+  this.setupDebug = function(callback) {
+    onBreakpointHit = callback;
+  }
+  this.clearDebug = function() {
+    debugSavedState = null;
+    debugTargetClock = 0;
+    debugClock = 0;
+    debugFrameStartClock = 0;
+    onBreakpointHit = null;
+    debugCondition = null;
+  }
+  this.breakpointHit = function() {
+    debugBreakState = self.saveState();
+    console.log("Breakpoint at clk", debugClock, "PC", debugBreakState.c.PC.toString(16));
+    this.pause();
+    if (onBreakpointHit) {
+      onBreakpointHit(debugBreakState);
+    }
+  }
+  this.step = function() {
+    var previousPC = -1;
+    self.setDebugCondition(function() {
+      if (debugClock++ >= debugTargetClock) {
+        var thisState = cpu.saveState();
+        if (previousPC < 0) {
+          previousPC = thisState.PC;
+        } else {
+          if (thisState.PC != previousPC && thisState.T == 0) {
+            //console.log(previousPC.toString(16), thisPC.toString(16));
+            debugTargetClock = debugClock-1;
+            self.breakpointHit();
+            return true;
+          }
+        }
+      }
+      return false;
+    });
+  }
+  this.runToPC = function(targetPC) {
+    var self = this;
+    self.setDebugCondition(function() {
+      if (debugClock++ >= debugTargetClock) {
+        var thisPC = cpu.saveState().PC;
+        if (thisPC == targetPC) {
+          self.breakpointHit();
+          debugTargetClock = debugClock;
+          return true;
+        } else {
+          return false;
+        }
+      }
+    });
+  }
+
+  this.loadState = function(state) {
+    cpu.loadState(state.c);
+    cpuram.mem.set(state.cb);
+    dvgram.mem.set(state.db);
+    nmicount = state.nmic;
+  }
+  this.saveState = function() {
+    return {
+      c:cpu.saveState(),
+      cb:cpuram.mem.slice(0),
+      db:dvgram.mem.slice(0),
+      nmic:nmicount
+    }
+  }
+  this.getRAMForState = function(state) {
+    return state.cb;
+  }
+}
+
+DVGStateMachine = function(bus, video) {
+  var self = this;
+  var pc = 0;
+  var x = 0;
+  var y = 0;
+  var gsc = 0;
+  var bofs = 0x4000;
+  var pcstack = [];
+  var running = false;
+
+  function readWord(a) {
+    a &= 0xfff;
+    return bus.read(a*2+bofs) + (bus.read(a*2+bofs+1) << 8);
+  }
+
+  function decodeSigned(w, o2) {
+    s = w & (1<<o2);
+    w = w & ((1<<o2)-1);
+    if (s)
+      return -w;
+    else
+      return w;
+  }
+
+  this.go = function() {
+    pc = 0;
+    gsc = 7;
+    running = true;
+  }
+
+  this.runUntilHalt = function() {
+    this.go();
+    for (var i=0; i<10000; i++) { // TODO
+      if (!running) break;
+      this.nextInstruction();
+    }
+    //console.log('DVG',i);
+  }
+
+  GSCALES = [7, 6, 5, 4, 3, 2, 1, 0, 15, 14, 13, 12, 11, 10, 9, 8];
+
+  this.nextInstruction = function() {
+    if (!running) return;
+    var w = readWord(pc);
+    var op = w >> 12;
+    //console.log(hex(pc), hex(w));
+    pc++;
+    switch (op) {
+      // VEC
+      case 0:
+      case 1:
+      case 2:
+      case 3:
+      case 4:
+      case 5:
+      case 6:
+      case 7:
+      case 8:
+      case 9: { // VCTR
+        var sc = gsc + 9 - op;
+        var w2 = readWord(pc++);
+        var z = w2 >> 12;
+        var x2 = x + ((decodeSigned(w2, 10) << 7) >> sc);
+        var y2 = y + ((decodeSigned(w, 10) << 7) >> sc);
+        video.drawLine(x, y, x2, y2, z);
+        //console.log(pc.toString(16), w.toString(16), w2.toString(16), gsc, sc, x, y, x2, y2);
+        x = x2;
+        y = y2;
+        break;
+      }
+      case 10: { // LABS
+        var w2 = readWord(pc++);
+        gsc = GSCALES[w2 >> 12];
+        x = w2 & 0x3ff;
+        y = w & 0x3ff;
+        break;
+      }
+      case 11: // HALT
+        running = false;
+        break;
+      case 13: // RTSL
+        pc = pcstack.pop();
+        break;
+      case 12: // JSRL
+        pcstack.push(pc);
+      case 14: // JMPL
+        pc = w & 0xfff;
+        break;
+      case 15: { // SVEC
+        var sc = ((w>>11)&1) + ((w>>2)&2);
+        sc = gsc - sc - 1;
+        var x2 = x + ((decodeSigned(w, 2) << 7) >> sc);
+        var y2 = y + ((decodeSigned(w>>8, 2) << 7) >> sc);
+        var z = (w >> 4) & 0xf;
+        video.drawLine(x, y, x2, y2, z);
+        x = x2;
+        y = y2;
+        break;
+      }
+    }
+  }
+}
diff --git a/src/platform/vcs.js b/src/platform/vcs.js
index 4d1e02a1..556ea784 100644
--- a/src/platform/vcs.js
+++ b/src/platform/vcs.js
@@ -29,6 +29,7 @@ var PRESETS = [
 //  {id:'examples/fullgame', name:'Thru Hike: The Game', title:'Thru Hike'},
 ];
 
+Javatari.AUTO_START = false;
 Javatari.SHOW_ERRORS = false;
 Javatari.CARTRIDGE_CHANGE_DISABLED = true;
 Javatari.DEBUG_SCANLINE_OVERFLOW = false; // TODO: make a switch
@@ -37,6 +38,10 @@ Javatari.AUDIO_BUFFER_SIZE = 256;
 VCSPlatform = function() {
   var self = this;
 
+  this.start = function() {
+    Javatari.start();
+  }
+
   this.loadROM = function(title, data) {
     Javatari.loadROM(title, data);
     this.current_output = data; // TODO: use bus
@@ -74,11 +79,12 @@ VCSPlatform = function() {
     Javatari.room.console.powerOn();
   }
   this.getOriginPC = function() {
-    return 0xf000; // TODO: read from vector
+    return (this.readAddress(0xfffc) | (this.readAddress(0xfffd) << 8)) & 0xffff;
   }
   this.readAddress = function(addr) {
     return current_output[addr - 0xf000]; // TODO: use bus to read
   }
+  this.getRAMForState = function(state) {
+    return jt.Util.byteStringToUInt8Array(atob(state.r.b));
+  }
 };
-
-platform = new VCSPlatform();
diff --git a/src/ui.js b/src/ui.js
index 080807ec..4d5cda74 100644
--- a/src/ui.js
+++ b/src/ui.js
@@ -1,4 +1,6 @@
 
+// 8bitworkshop IDE user interface
+
 var worker = new Worker("./src/worker/workermain.js");
 var current_output = null;
 var current_preset_idx = -1; // TODO: use URL
@@ -125,10 +127,6 @@ function _shareFile(e) {
     alert("Please fix errors before sharing.");
     return true;
   }
-  if (current_preset_idx < 0) {
-    alert("Can only reset built-in file examples.")
-    return true;
-  }
   var text = editor.getValue();
   console.log("POST",text.length,'bytes');
   $.post({
@@ -152,8 +150,9 @@ function _shareFile(e) {
 }
 
 function _resetPreset(e) {
-  if (current_preset_idx >= 0
-    && confirm("Reset '" + PRESETS[current_preset_idx].name + "' to default?")) {
+  if (current_preset_idx < 0) {
+    alert("Can only reset built-in file examples.")
+  } else if (confirm("Reset '" + PRESETS[current_preset_idx].name + "' to default?")) {
     qs['reset'] = '1';
     window.location = "?" + $.param(qs);
   }
@@ -232,7 +231,7 @@ worker.onmessage = function(e) {
     editor.clearGutter("gutter-info");
     for (info of e.data.listing.errors) {
       var div = document.createElement("div");
-      div.setAttribute("class", "tooltip tooltiperror");
+      div.setAttribute("class", "tooltipbox tooltiperror");
       div.style.color = '#ff3333'; // TODO
       div.appendChild(document.createTextNode("\u24cd"));
       var tooltip = document.createElement("span");
@@ -377,8 +376,8 @@ function showMemory(state) {
   if (state) {
     s = cpuStateToLongString(state.c);
     s += "\n";
-    var ram = jt.Util.byteStringToUInt8Array(atob(state.r.b));
-    // TODO: show entire RAM for other platforms
+    var ram = platform.getRAMForState(state);
+    // TODO: show scrollable RAM for other platforms
     for (var ofs=0; ofs<0x80; ofs+=0x10) {
       s += '$' + hex(ofs+0x80) + ':';
       for (var i=0; i<0x10; i++) {
@@ -636,15 +635,11 @@ function showLoopTimingForCurrentLine() {
 }
 */
 
-function reset() {
-  platform.reset();
-}
-
 function resetAndDebug() {
-  reset();
+  platform.reset();
   runToCursor();
-}
 
+}
 function setupDebugControls(){
   $("#dbg_reset").click(resetAndDebug);
   $("#dbg_pause").click(pause);
@@ -718,8 +713,10 @@ var qs = (function (a) {
     return b;
 })(window.location.search.substr(1).split('&'));
 
+// start
 setupDebugControls();
 showWelcomeMessage();
+// parse query string
 try {
   // is this a share URL?
   if (qs['sharekey']) {
@@ -753,6 +750,19 @@ try {
       var lastid = localStorage.getItem("__lastid");
       gotoPresetNamed(lastid || PRESETS[0].id);
     }
+    // load and start platform object
+    if (qs['platform'] == 'vcs') {
+      platform = new VCSPlatform();
+      platform.start();
+    } else if (qs['platform'] == 'apple2') {
+      platform = new Apple2Platform($("#emulator")[0]);
+      platform.start();
+    } else if (qs['platform'] == 'atarivec') {
+      platform = new AtariVectorPlatform($("#emulator")[0]);
+      platform.start();
+    } else {
+      alert("Platform " + qs['platform'] + " not recognized");
+    }
   }
 } catch (e) {
   alert(e+""); // TODO?
diff --git a/src/util.js b/src/util.js
new file mode 100644
index 00000000..da723219
--- /dev/null
+++ b/src/util.js
@@ -0,0 +1,207 @@
+
+function lzgmini() {
+
+  // Constants
+  var LZG_HEADER_SIZE = 16;
+  var LZG_METHOD_COPY = 0;
+  var LZG_METHOD_LZG1 = 1;
+
+  // LUT for decoding the copy length parameter
+  var LZG_LENGTH_DECODE_LUT = [2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,
+                               20,21,22,23,24,25,26,27,28,29,35,48,72,128];
+
+  // Decoded data (produced by the decode() method)
+  var outdata = null;
+
+  // Calculate the checksum
+  var calcChecksum = function(data) {
+    var a = 1;
+    var b = 0;
+    var i = LZG_HEADER_SIZE;
+    while (i < data.length)
+    {
+      a = (a + (data[i] & 0xff)) & 0xffff;
+      b = (b + a) & 0xffff;
+      i++;
+    }
+    return (b << 16) | a;
+  }
+
+  // Decode LZG coded data. The function returns the size of the decoded data.
+  // Use any of the get* methods to retrieve the decoded data.
+  this.decode = function(data) {
+    // Start by clearing the decompressed array in this object
+    outdata = null;
+
+    // Check magic ID
+    if ((data.length < LZG_HEADER_SIZE) || (data[0] != 76) ||
+         (data[1] != 90) || (data[2] != 71))
+    {
+      return 0;
+    }
+
+    // Calculate & check the checksum
+    var checksum = ((data[11] & 0xff) << 24) |
+                   ((data[12] & 0xff) << 16) |
+                   ((data[13] & 0xff) << 8) |
+                   (data[14] & 0xff);
+    if (calcChecksum(data) != checksum)
+    {
+      return 0;
+    }
+
+    // Check which method to use
+    var method = data[15] & 0xff;
+    if (method == LZG_METHOD_LZG1)
+    {
+      // Get marker symbols
+      var m1 = data[16] & 0xff;
+      var m2 = data[17] & 0xff;
+      var m3 = data[18] & 0xff;
+      var m4 = data[19] & 0xff;
+
+      // Main decompression loop
+      var symbol, b, b2, b3, len, offset;
+      var dst = new Array();
+      var dstlen = 0;
+      var k = LZG_HEADER_SIZE + 4;
+      var datalen = data.length;
+      while (k <= datalen)
+      {
+        symbol = data[k++] & 0xff;
+        if ((symbol != m1) && (symbol != m2) && (symbol != m3) && (symbol != m4))
+        {
+          // Literal copy
+          dst[dstlen++] = symbol;
+        }
+        else
+        {
+          b = data[k++] & 0xff;
+          if (b != 0)
+          {
+            // Decode offset / length parameters
+            if (symbol == m1)
+            {
+              // marker1 - "Distant copy"
+              len = LZG_LENGTH_DECODE_LUT[b & 0x1f];
+              b2 = data[k++] & 0xff;
+              b3 = data[k++] & 0xff;
+              offset = (((b & 0xe0) << 11) | (b2 << 8) | b3) + 2056;
+            }
+            else if (symbol == m2)
+            {
+              // marker2 - "Medium copy"
+              len = LZG_LENGTH_DECODE_LUT[b & 0x1f];
+              b2 = data[k++] & 0xff;
+              offset = (((b & 0xe0) << 3) | b2) + 8;
+            }
+            else if (symbol == m3)
+            {
+              // marker3 - "Short copy"
+              len = (b >> 6) + 3;
+              offset = (b & 63) + 8;
+            }
+            else
+            {
+              // marker4 - "Near copy (incl. RLE)"
+              len = LZG_LENGTH_DECODE_LUT[b & 0x1f];
+              offset = (b >> 5) + 1;
+            }
+
+            // Copy the corresponding data from the history window
+            for (i = 0; i < len; i++)
+            {
+              dst[dstlen] = dst[dstlen-offset];
+              dstlen++;
+            }
+          }
+          else
+          {
+            // Literal copy (single occurance of a marker symbol)
+            dst[dstlen++] = symbol;
+          }
+        }
+      }
+
+      // Store the decompressed data in the lzgmini object for later retrieval
+      outdata = dst;
+      return outdata;
+    }
+    else if (method == LZG_METHOD_COPY)
+    {
+      // Plain copy
+      var dst = new Array();
+      var dstlen = 0;
+      var datalen = data.length;
+      for (var i = LZG_HEADER_SIZE; i < datalen; i++)
+      {
+        dst[dstlen++] = data[i] & 0xff;
+      }
+      outdata = dst;
+      return outdata;
+    }
+    else
+    {
+      // Unknown method
+      return null;
+    }
+  }
+
+  // Get the decoded byte array
+  this.getByteArray = function()
+  {
+    return outdata;
+  }
+
+  // Get the decoded string from a Latin 1 (or ASCII) encoded array
+  this.getStringLatin1 = function()
+  {
+    var str = "";
+    if (outdata != null)
+    {
+      var charLUT = new Array();
+      for (var i = 0; i < 256; ++i)
+        charLUT[i] = String.fromCharCode(i);
+      var outlen = outdata.length;
+      for (var i = 0; i < outlen; i++)
+        str += charLUT[outdata[i]];
+    }
+    return str;
+  }
+
+  // Get the decoded string from an UTF-8 encoded array
+  this.getStringUTF8 = function()
+  {
+    var str = "";
+    if (outdata != null)
+    {
+      var charLUT = new Array();
+      for (var i = 0; i < 128; ++i)
+        charLUT[i] = String.fromCharCode(i);
+      var c;
+      var outlen = outdata.length;
+      for (var i = 0; i < outlen;)
+      {
+        c = outdata[i++];
+        if (c < 128)
+        {
+          str += charLUT[c];
+        }
+        else
+        {
+          if ((c > 191) && (c < 224))
+          {
+            c = ((c & 31) << 6) | (outdata[i++] & 63);
+          }
+          else
+          {
+            c = ((c & 15) << 12) | ((outdata[i] & 63) << 6) | (outdata[i+1] & 63);
+            i += 2;
+          }
+          str += String.fromCharCode(c);
+        }
+      }
+    }
+    return str;
+  }
+}