mirror of
https://github.com/sehugg/8bitworkshop.git
synced 2024-09-30 13:54:55 +00:00
197 lines
5.1 KiB
JavaScript
197 lines
5.1 KiB
JavaScript
"use strict";
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// http://www.computerarcheology.com/Arcade/
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var MW8080BW_PRESETS = [
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{id:'game2.c', name:'Game #2'},
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];
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var Midway8080BWPlatform = function(mainElement) {
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var self = this;
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this.__proto__ = new BaseZ80Platform();
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var cpu, ram, membus, iobus, rom;
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var video, timer, pixels, displayPCs;
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var inputs = [0xe,0x8,0x0];
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var bitshift_offset = 0;
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var bitshift_register = 0;
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var watchdog_counter;
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var cpuFrequency = 1996800;
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var cpuCyclesPerLine = cpuFrequency/(60*224); // TODO
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var INITIAL_WATCHDOG = 256;
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var PIXEL_ON = 0xffeeeeee;
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var PIXEL_OFF = 0xff000000;
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var SPACEINV_KEYCODE_MAP = makeKeycodeMap([
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[Keys.VK_SPACE, 1, 0x10], // P1
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[Keys.VK_LEFT, 1, 0x20],
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[Keys.VK_RIGHT, 1, 0x40],
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[Keys.VK_S, 2, 0x10], // P2
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[Keys.VK_A, 2, 0x20],
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[Keys.VK_D, 2, 0x40],
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[Keys.VK_5, 1, 0x1],
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[Keys.VK_1, 1, 0x4],
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[Keys.VK_2, 1, 0x2],
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]);
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this.getPresets = function() {
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return MW8080BW_PRESETS;
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}
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this.start = function() {
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ram = new RAM(0x2000);
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displayPCs = new Uint16Array(new ArrayBuffer(0x2000*2));
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membus = {
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read: new AddressDecoder([
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[0x0000, 0x1fff, 0x1fff, function(a) { return rom ? rom[a] : 0; }],
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[0x2000, 0x3fff, 0x1fff, function(a) { return ram.mem[a]; }],
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]),
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write: new AddressDecoder([
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[0x2000, 0x23ff, 0x3ff, function(a,v) { ram.mem[a] = v; }],
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[0x2400, 0x3fff, 0x1fff, function(a,v) {
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ram.mem[a] = v;
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var ofs = (a - 0x400)<<3;
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for (var i=0; i<8; i++)
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pixels[ofs+i] = (v & (1<<i)) ? PIXEL_ON : PIXEL_OFF;
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displayPCs[a] = cpu.getPC(); // save program counter
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}],
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]),
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isContended: function() { return false; },
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};
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iobus = {
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read: function(addr) {
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addr &= 0x3;
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//console.log('IO read', hex(addr,4));
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switch (addr) {
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case 0:
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case 1:
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case 2:
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return inputs[addr];
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case 3:
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return (bitshift_register >> (8-bitshift_offset)) & 0xff;
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}
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return 0;
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},
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write: function(addr, val) {
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addr &= 0x7;
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val &= 0xff;
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//console.log('IO write', hex(addr,4), hex(val,2));
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switch (addr) {
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case 2:
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bitshift_offset = val & 0x7;
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break;
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case 3:
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case 5:
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// TODO: sound
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break;
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case 4:
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bitshift_register = (bitshift_register >> 8) | (val << 8);
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break;
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case 6:
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watchdog_counter = INITIAL_WATCHDOG;
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break;
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}
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}
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};
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cpu = window.Z80({
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display: {},
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memory: membus,
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ioBus: iobus
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});
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video = new RasterVideo(mainElement,256,224,{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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setKeyboardFromMap(video, inputs, SPACEINV_KEYCODE_MAP);
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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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var targetTstates = cpu.getTstates();
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for (var sl=0; sl<224; sl++) {
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targetTstates += cpuCyclesPerLine;
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if (debugCond) {
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while (cpu.getTstates() < 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.runFrame(cpu.getTstates() + 1);
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}
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if (!debugCond)
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break;
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} else {
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cpu.runFrame(targetTstates);
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}
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if (sl == 95)
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cpu.requestInterrupt(0x8); // RST $8
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else if (sl == 223)
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cpu.requestInterrupt(0x10); // RST $10
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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"); // TODO: alert on video
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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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rom = padBytes(data, 0x2000);
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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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bitshift_register = state.bsr;
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bitshift_offset = state.bso;
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watchdog_counter = state.wdc;
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inputs[0] = state.in0;
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inputs[1] = state.in1;
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inputs[2] = state.in2;
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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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bsr:bitshift_register,
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bso:bitshift_offset,
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wdc:watchdog_counter,
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in0:inputs[0],
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in1:inputs[1],
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in2:inputs[2],
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};
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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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cpu.setTstates(0);
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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['mw8080bw'] = Midway8080BWPlatform;
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