mirror of
https://github.com/sehugg/8bitworkshop.git
synced 2024-05-28 08:41:30 +00:00
225 lines
7.4 KiB
JavaScript
225 lines
7.4 KiB
JavaScript
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"use strict";
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var WILLIAMS_PRESETS = [
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];
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var WilliamsPlatform = function(mainElement) {
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var self = this;
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this.__proto__ = new Base6809Platform();
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var cpu, ram, membus, iobus, rom, nvram;
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var video, timer, pixels, displayPCs;
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var banksel = 0;
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var watchdog_counter;
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var video_counter;
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var pia6821 = [0,0,0,0,0,0,0,0];
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var screenNeedsRefresh = false;
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var xtal = 12000000;
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var cpuFrequency = xtal/3/4;
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var cpuCyclesPerFrame = cpuFrequency/60; // TODO
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var INITIAL_WATCHDOG = 64;
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var PIXEL_ON = 0xffeeeeee;
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var PIXEL_OFF = 0xff000000;
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var KEYCODE_MAP = makeKeycodeMap([
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[Keys.VK_SPACE, 4, 0x1],
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[Keys.VK_RIGHT, 4, 0x2],
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[Keys.VK_Z, 4, 0x4],
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[Keys.VK_X, 4, 0x8],
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[Keys.VK_2, 4, 0x10],
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[Keys.VK_1, 4, 0x20],
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[Keys.VK_LEFT, 4, 0x40],
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[Keys.VK_DOWN, 4, 0x80],
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[Keys.VK_UP, 6, 0x1],
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[Keys.VK_5, 0, 0x4],
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[Keys.VK_7, 0, 0x1],
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[Keys.VK_8, 0, 0x2],
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[Keys.VK_9, 0, 0x8],
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]);
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var palette = [];
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for (var ii=0; ii<16; ii++)
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palette[ii] = 0xff000000;
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this.getPresets = function() {
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return WILLIAMS_PRESETS;
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}
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var ioread = new AddressDecoder([
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[0x400, 0x5ff, 0x1ff, function(a) { return nvram.mem[a]; }],
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[0x800, 0x800, 0, function(a) { return video_counter; }],
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[0xc00, 0xc07, 0x7, function(a) { return pia6821[a]; }],
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[0x0, 0xfff, 0, function(a) { console.log('ioread',hex(a)); }],
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]);
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var iowrite = new AddressDecoder([
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[0x0, 0xf, 0xf, function(a,v) {
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// RRRGGGBB
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var color = 0xff000000 | ((v&7)<<5) | (((v>>3)&7)<<13) | (((v>>6)<<22));
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if (color != palette[a]) {
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palette[a] = color;
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screenNeedsRefresh = true;
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}
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}],
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[0x3fc, 0x3ff, 0, function(a,v) { if (v == 56) watchdog_counter = INITIAL_WATCHDOG; }], // TODO: check value?
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[0x400, 0x5ff, 0x1ff, function(a,v) { nvram.mem[a] = v; }],
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[0xc00, 0xc07, 0x7, function(a,v) { pia6821[a] = v; }],
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[0x0, 0xfff, 0, function(a,v) { console.log('iowrite',hex(a),hex(v)); }],
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]);
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function drawDisplayByte(a,v) {
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var ofs = ((a&0xff00)<<1) | ((a&0xff)^0xff);
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pixels[ofs] = palette[v>>4];
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pixels[ofs+256] = palette[v&0xf];
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}
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this.start = function() {
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ram = new RAM(0xc000);
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nvram = new RAM(0x200);
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// TODO: save in browser storage?
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nvram.mem.set([240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,242,241,242,247,240,244,244,245,242,244,250,240,241,248,243,241,245,245,243,244,241,244,253,240,241,245,249,242,240,244,252,244,245,244,244,240,241,244,242,248,245,245,240,244,247,244,244,240,241,242,245,242,240,244,243,245,242,244,242,240,241,241,240,243,245,244,253,245,242,245,243,240,240,248,242,246,245,245,243,245,243,245,242,240,240,246,240,241,240,245,244,244,253,244,248,240,240,245,250,240,241,240,240,240,243,240,243,240,241,240,244,240,241,240,241,240,240,240,240,240,240,240,245,241,245,240,241,240,245,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240,240]);
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displayPCs = new Uint16Array(new ArrayBuffer(0x9800*2));
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rom = padBytes(new lzgmini().decode(DEFENDER_ROM).slice(0), 0x7000);
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membus = {
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read: new AddressDecoder([
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[0x0000, 0xbfff, 0xffff, function(a) { return ram.mem[a]; }],
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[0xc000, 0xcfff, 0x0fff, function(a) {
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switch (banksel) {
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case 0: return ioread(a);
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case 1: return rom[a+0x3000];
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case 2: return rom[a+0x4000];
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case 3: return rom[a+0x5000];
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case 4:
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case 5:
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case 6:
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case 7: return rom[a+0x6000];
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default: return 0; // TODO: error light
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}
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}],
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[0xd000, 0xffff, 0xffff, function(a) { return rom ? rom[a-0xd000] : 0; }],
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]),
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write: new AddressDecoder([
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[0x9800, 0xbfff, 0, function(a,v) { ram.mem[a] = v; }],
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[0x0000, 0x97ff, 0, function(a,v) {
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ram.mem[a] = v;
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drawDisplayByte(a, v);
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displayPCs[a] = cpu.getPC(); // save program counter
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}],
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[0xc000, 0xcfff, 0x0fff, iowrite],
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[0xd000, 0xdfff, 0, function(a,v) { banksel = v&0x7; }],
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[0, 0xffff, 0, function(a,v) { console.log(hex(a), hex(v)); }],
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]),
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};
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cpu = new CPU6809();
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cpu.init(membus.write, membus.read, 0);
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video = new RasterVideo(mainElement,256,304,{rotate:-90});
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video.create();
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$(video.canvas).click(function(e) {
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var x = Math.floor(e.offsetX * video.canvas.width / $(video.canvas).width());
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var y = Math.floor(e.offsetY * video.canvas.height / $(video.canvas).height());
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var addr = (x>>3) + (y*32) + 0x400;
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console.log(x, y, hex(addr,4), "PC", hex(displayPCs[addr],4));
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});
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var idata = video.getFrameData();
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video.setKeyboardEvents(function(key,code,flags) {
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var o = KEYCODE_MAP[key];
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if (o) {
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console.log(key,code,flags,o);
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if (flags & 1) {
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pia6821[o.index] |= o.mask;
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} else {
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pia6821[o.index] &= ~o.mask;
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}
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}
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});
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pixels = video.getFrameData();
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timer = new AnimationTimer(60, function() {
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if (!self.isRunning())
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return;
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var debugCond = self.getDebugCallback();
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// interrupts happen every 1/4 of the screen
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for (var quarter=0; quarter<4; quarter++) {
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video_counter = (quarter & 1) ? 0xff : 0x00;
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if (pia6821[7] == 0x3c) { // TODO?
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cpu.interrupt();
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//console.log(cpu.getPC());
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}
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var targetTstates = cpu.T() + cpuCyclesPerFrame/4;
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if (debugCond) {
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while (cpu.T() < targetTstates) {
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if (debugCond && debugCond()) {
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debugCond = null;
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break;
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}
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cpu.steps(1);
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}
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} else {
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cpu.steps(cpuCyclesPerFrame);
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}
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}
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if (screenNeedsRefresh) {
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for (var i=0; i<0x9800; i++)
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drawDisplayByte(i, ram.mem[i]);
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screenNeedsRefresh = false;
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}
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video.updateFrame();
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if (watchdog_counter-- <= 0) {
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console.log("WATCHDOG FIRED, PC =", cpu.getPC().toString(16)); // TODO: alert on video
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// TODO: self.breakpointHit(cpu.T());
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self.reset();
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}
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self.restartDebugState();
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});
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}
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this.loadROM = function(title, data) {
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// TODO
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self.reset();
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}
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this.loadState = function(state) {
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cpu.loadState(state.c);
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ram.mem.set(state.b);
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nvram.mem.set(state.nvram);
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watchdog_counter = state.wdc;
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banksel = state.bs;
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pia6821 = state.pia;
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}
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this.saveState = function() {
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return {
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c:self.getCPUState(),
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b:ram.mem.slice(0),
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nvram:nvram.mem.slice(0),
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wdc:watchdog_counter,
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bs:banksel,
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pia:pia6821,
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};
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}
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this.getRAMForState = function(state) {
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return ram.mem;
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}
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this.getCPUState = function() {
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return cpu.saveState();
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}
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this.isRunning = function() {
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return timer.isRunning();
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}
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this.pause = function() {
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timer.stop();
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}
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this.resume = function() {
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timer.start();
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}
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this.reset = function() {
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cpu.reset();
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watchdog_counter = INITIAL_WATCHDOG;
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}
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this.readAddress = function(addr) {
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return membus.read(addr);
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}
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}
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PLATFORMS['williams'] = WilliamsPlatform;
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