146 lines
3.8 KiB
TypeScript
146 lines
3.8 KiB
TypeScript
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import { Z80, Z80State } from "../common/cpu/ZilogZ80";
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import { BasicScanlineMachine } from "../common/devices";
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import { KeyFlags, newAddressDecoder, padBytes, Keys, makeKeycodeMap, newKeyboardHandler } from "../common/emu";
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import { TssChannelAdapter, MasterAudio, AY38910_Audio } from "../common/audio";
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// http://www.computerarcheology.com/Arcade/
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const SPACEINV_KEYCODE_MAP = makeKeycodeMap([
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[Keys.A, 1, 0x10], // P1
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[Keys.LEFT, 1, 0x20],
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[Keys.RIGHT, 1, 0x40],
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[Keys.P2_A, 2, 0x10], // P2
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[Keys.P2_LEFT, 2, 0x20],
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[Keys.P2_RIGHT, 2, 0x40],
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[Keys.SELECT, 1, 0x1],
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[Keys.START, 1, 0x4],
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[Keys.P2_START, 1, 0x2],
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]);
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const INITIAL_WATCHDOG = 256;
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const PIXEL_ON = 0xffeeeeee;
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const PIXEL_OFF = 0xff000000;
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export class Midway8080 extends BasicScanlineMachine {
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cpuFrequency = 1996800; // MHz
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canvasWidth = 256;
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numTotalScanlines = 262;
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numVisibleScanlines = 224;
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cpuCyclesPerLine = Math.floor(1996800 / (262*60));
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defaultROMSize = 0x2000;
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rotate = -90;
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sampleRate = 1;
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bitshift_offset = 0;
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bitshift_register = 0;
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watchdog_counter;
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cpu: Z80 = new Z80();
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ram = new Uint8Array(0x2000);
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constructor() {
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super();
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this.connectCPUMemoryBus(this);
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this.connectCPUIOBus(this.newIOBus());
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this.handler = newKeyboardHandler(this.inputs, SPACEINV_KEYCODE_MAP);
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}
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read = newAddressDecoder([
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[0x0000, 0x1fff, 0x1fff, (a) => { return this.rom ? this.rom[a] : 0; }],
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[0x2000, 0x3fff, 0x1fff, (a) => { return this.ram[a]; }],
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]);
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write = newAddressDecoder([
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[0x2000, 0x23ff, 0x3ff, (a, v) => { this.ram[a] = v; }],
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[0x2400, 0x3fff, 0x1fff, (a, v) => {
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this.ram[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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this.pixels[ofs + i] = (v & (1 << i)) ? PIXEL_ON : PIXEL_OFF;
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}
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//if (displayPCs) displayPCs[a] = cpu.getPC(); // save program counter
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}],
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]);
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newIOBus() {
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return {
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read: (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 this.inputs[addr];
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case 3:
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return (this.bitshift_register >> (8 - this.bitshift_offset)) & 0xff;
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}
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return 0;
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},
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write: (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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this.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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this.bitshift_register = (this.bitshift_register >> 8) | (val << 8);
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break;
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case 6:
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this.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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}
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startScanline() {
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}
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drawScanline() {
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// at end of scanline
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if (this.scanline == 95)
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this.interrupt(0xcf); // RST $8
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else if (this.scanline == 223)
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this.interrupt(0xd7); // RST $10
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}
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interrupt(data:number) {
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this.probe.logInterrupt(data);
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this.cpu.interrupt(data);
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}
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advanceFrame(trap) : number {
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if (this.watchdog_counter-- <= 0) {
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console.log("WATCHDOG FIRED"); // TODO: alert on video
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this.reset();
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}
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return super.advanceFrame(trap);
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}
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loadState(state) {
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super.loadState(state);
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this.bitshift_register = state.bsr;
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this.bitshift_offset = state.bso;
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this.watchdog_counter = state.wdc;
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}
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saveState() {
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var state: any = super.saveState();
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state.bsr = this.bitshift_register;
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state.bso = this.bitshift_offset;
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state.wdc = this.watchdog_counter;
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return state;
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}
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reset() {
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super.reset();
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this.watchdog_counter = INITIAL_WATCHDOG;
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}
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}
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