mirror of
https://github.com/sehugg/8bitworkshop.git
synced 2024-10-01 04:56:14 +00:00
382 lines
11 KiB
JavaScript
382 lines
11 KiB
JavaScript
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"use strict";
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var GALAXIAN_PRESETS = [
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];
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// TODO: global???
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window.buildZ80({
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applyContention: false
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});
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var GalaxianPlatform = function(mainElement) {
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var self = this;
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this.__proto__ = new BaseZ80Platform();
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var cpu, ram, vram, oram, membus, iobus, rom, palette, outlatches;
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var video, audio, timer, pixels, displayPCs;
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var inputs = [0xe,0x8,0x0];
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var interruptEnabled = 0;
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var starsEnabled = 0;
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var watchdog_counter;
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var frameCounter = 0;
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var XTAL = 18432000.0;
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var scanlinesPerFrame = 264;
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var cpuFrequency = XTAL/6; // 3.072 MHz
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var hsyncFrequency = XTAL/3/192/2; // 16 kHz
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var vsyncFrequency = hsyncFrequency/132/2; // 60.606060 Hz
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var vblankDuration = 1/vsyncFrequency * (20/132); // 2500 us
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var cpuCyclesPerLine = cpuFrequency/hsyncFrequency;
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var INITIAL_WATCHDOG = 256;
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var showOffscreenObjects = false;
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var stars = [];
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for (var i=0; i<256; i++)
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stars[i] = noise();
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function drawScanline(pixels, sl) {
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if (sl < 16 && !showOffscreenObjects) return; // offscreen
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if (sl >= 240 && !showOffscreenObjects) return; // offscreen
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// draw tiles
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var pixofs = sl*264;
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var outi = pixofs; // starting output pixel in frame buffer
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for (var xx=0; xx<32; xx++) {
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var xofs = xx;
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var scroll = oram.mem[xofs*2]; // even entries control scroll position
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var attrib = oram.mem[xofs*2+1]; // odd entries control the color base
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var sl2 = (sl + scroll) & 0xff;
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var vramofs = (sl2>>3)<<5; // offset in VRAM
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var yy = sl2 & 7; // y offset within tile
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var tile = vram.mem[vramofs+xofs];
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var color0 = (attrib & 7) << 2;
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var addr = 0x2800+(tile<<3)+yy;
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var data1 = rom[addr];
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var data2 = rom[addr+0x800];
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for (var i=0; i<8; i++) {
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var bm = 128>>i;
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var color = color0 + ((data1&bm)?1:0) + ((data2&bm)?2:0);
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pixels[outi] = palette[color];
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outi++;
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}
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}
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// draw sprites
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for (var sprnum=7; sprnum>=0; sprnum--) {
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var base = (sprnum<<2) + 0x40;
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var base0 = oram.mem[base];
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var sy = 240 - (base0 - (sprnum<3)); // the first three sprites match against y-1
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var yy = (sl - sy);
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if (yy >= 0 && yy < 16) {
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var sx = oram.mem[base+3] + 1; // +1 pixel offset from tiles
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if (sx == 0 && !showOffscreenObjects)
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continue; // drawn off-buffer
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var code = oram.mem[base+1];
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var flipx = code & 0x40; // TODO
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var flipy = code & 0x80; // TODO
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code &= 0x3f;
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var color0 = oram.mem[base+2] << 2;
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var addr = 0x2800+(code<<5)+(yy<8?yy:yy+8);
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outi = pixofs + sx; //<< 1
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var data1 = rom[addr];
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var data2 = rom[addr+0x800];
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for (var i=0; i<8; i++) {
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var bm = 128>>i;
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var color = ((data1&bm)?1:0) + ((data2&bm)?2:0);
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if (color)
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pixels[outi+i] = palette[color0 + color];
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}
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var data1 = rom[addr+8];
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var data2 = rom[addr+0x808];
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for (var i=0; i<8; i++) {
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var bm = 128>>i;
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var color = ((data1&bm)?1:0) + ((data2&bm)?2:0);
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if (color)
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pixels[outi+i+8] = palette[color0 + color];
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}
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}
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}
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// draw bullets/shells
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var shell = 0xff;
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var missile = 0xff;
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for (var which=0; which<8; which++) {
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var sy = oram.mem[0x60 + (which<<2)+1];
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if (((sy + sl - (which<3))&0xff) == 0xff) {
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if (which != 7)
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shell = which;
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else
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missile = which;
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}
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}
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for (var which of [shell,missile]) {
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if (which != 0xff) {
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var sx = 255 - oram.mem[0x60 + (which<<2)+3];
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var outi = pixofs+sx;
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var col = which == 7 ? 0xffffff00 : 0xffffffff;
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pixels[outi++] = col;
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pixels[outi++] = col;
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pixels[outi++] = col;
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pixels[outi++] = col;
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}
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}
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// draw stars
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if (starsEnabled) {
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var starx = ((frameCounter + stars[sl & 0xff]) & 0xff);
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if ((starx + sl) & 0x10) {
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var outi = pixofs + starx;
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if ((pixels[outi] & 0xffffff) == 0) {
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pixels[outi] = palette[sl & 0x1f];
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}
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}
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}
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}
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var KEYCODE_MAP = {
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32:{i:0,b:4}, // space bar (P1)
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37:{i:0,b:2}, // left arrow (P1)
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39:{i:0,b:3}, // right arrow (P1)
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0x53:{i:1,b:4}, // S (P2)
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0x41:{i:1,b:2}, // A (P2)
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0x44:{i:1,b:3}, // D (P2)
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53:{i:0,b:0}, // 5
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49:{i:1,b:0}, // 1
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50:{i:1,b:1}, // 2
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}
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this.getPresets = function() {
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return GALAXIAN_PRESETS;
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}
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this.start = function() {
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ram = new RAM(0x400);
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vram = new RAM(0x400);
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oram = new RAM(0x100);
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outlatches = new RAM(0x8);
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membus = {
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read: function(address) {
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if (address < 0x4000) {
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return (rom ? rom[address] : 0) & 0xff;
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} else if (address < 0x4800) {
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address &= 0x3ff;
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return ram.mem[address] & 0xff;
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} else if (address >= 0x5000 && address < 0x5800) {
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address &= 0x3ff;
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return vram.mem[address] & 0xff;
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} else if (address >= 0x5800 && address < 0x6000) {
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address &= 0xff;
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return oram.mem[address] & 0xff;
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} else if (address >= 0x6000 && address < 0x6800) {
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address &= 0x7;
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switch (address) {
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case 0:
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return inputs[0];
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}
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} else if (address >= 0x6800 && address < 0x7000) {
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return inputs[1];
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} else if (address >= 0x7000 && address < 0x7800) {
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address &= 0x7;
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switch (address) {
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case 0:
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return inputs[2];
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}
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} else if (address >= 0x7800 && address < 0x8000) {
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watchdog_counter = INITIAL_WATCHDOG;
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} else {
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console.log("read", hex(address));
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return 0;
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}
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},
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write: function(address, value) {
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//console.log("write", hex(address,4), hex(value,2));
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if (address >= 0x4000 && address < 0x4800) {
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address &= 0x3ff;
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ram.mem[address] = value;
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} else if (address >= 0x5000 && address < 0x5800) {
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address &= 0x3ff;
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vram.mem[address] = value;
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} else if (address >= 0x5800 && address < 0x6000) {
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address &= 0xff;
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oram.mem[address] = value;
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} else if (address >= 0x6000 && address < 0x6800) {
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address &= 0x7;
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outlatches.mem[address] = value;
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} else if (address >= 0x6800 && address < 0x7000) {
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address &= 0x7;
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// TODO: sound
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} else if (address >= 0x7000 && address < 0x7800) {
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address &= 0x7;
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switch (address) {
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case 1:
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interruptEnabled = value;
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break;
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case 4:
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starsEnabled = value;
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break;
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}
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} else if (address >= 0x7800 && address < 0x8000) {
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// TODO: sound
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} else {
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console.log("write", hex(address), hex(value));
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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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console.log('IO read', hex(addr,4));
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return 0;
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},
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write: function(addr, val) {
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console.log('IO write', hex(addr,4), hex(val,2));
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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,264,264,{rotate:90});
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audio = new SampleAudio(cpuFrequency);
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video.create();
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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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if (flags & 1) {
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inputs[o.i] |= (1<<o.b);
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} else {
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inputs[o.i] &= ~(1<<o.b);
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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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var targetTstates = cpu.getTstates();
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for (var sl=0; sl<scanlinesPerFrame; sl++) {
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drawScanline(pixels, 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()) { debugCond = null; }
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cpu.runFrame(cpu.getTstates() + 1);
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}
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} else {
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cpu.runFrame(targetTstates);
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}
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}
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// visible area is 256x224 (before rotation)
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video.updateFrame(0, 0, 0, 0, showOffscreenObjects ? 264 : 256, 264);
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frameCounter = (frameCounter + 1) & 0xff;
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if (watchdog_counter-- <= 0) {
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console.log("WATCHDOG FIRED, PC ", hex(cpu.getPC())); // TODO: alert on video
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self.reset();
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}
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self.restartDebugState();
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// NMI interrupt @ 0x66
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if (interruptEnabled) { cpu.nonMaskableInterrupt(); }
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});
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}
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var bitcolors = [
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0x000021, 0x000047, 0x000097, // red
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0x002100, 0x004700, 0x009700, // green
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0x510000, 0xae0000 // blue
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];
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this.loadROM = function(title, data) {
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rom = padBytes(data, 0x4000);
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palette = new Uint32Array(new ArrayBuffer(32*4));
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for (var i=0; i<32; i++) {
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var b = rom[0x3800+i];
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palette[i] = 0xff000000;
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for (var j=0; j<8; j++)
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if (((1<<j) & b))
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palette[i] += bitcolors[j];
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}
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self.reset();
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/*
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// skip self-test
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for (var i=0 ;i<3000; i++) {
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cpu.runFrame(cpu.getTstates() + cpuCyclesPerLine*scanlinesPerFrame);
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if (interruptEnabled) { cpu.nonMaskableInterrupt(); }
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}
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function arr2arr(a) {
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var l = 0;
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while (a[++l] >= 0) ;
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var arr = new Uint8Array(new ArrayBuffer(l));
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for (var i=0; i<l; i++)
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arr[i] = a[i];
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return arr;
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}
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state.b = arr2arr(state.b);
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state.bv = arr2arr(state.bv);
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state.bo = arr2arr(state.bo);
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this.loadState(state);
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*/
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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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vram.mem.set(state.bv);
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oram.mem.set(state.bo);
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watchdog_counter = state.wdc;
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interruptEnabled = state.ie;
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starsEnabled = state.se;
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frameCounter = fc;
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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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bv:vram.mem.slice(0),
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bo:oram.mem.slice(0),
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fc:frameCounter,
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ie:interruptEnabled,
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se:starsEnabled,
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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.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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audio.stop();
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console.log(JSON.stringify(this.saveState()));
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}
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this.resume = function() {
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timer.start();
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audio.start();
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}
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this.reset = function() {
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cpu.reset();
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if (!this.getDebugCallback()) cpu.setTstates(0); // TODO?
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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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this.ramStateToLongString = function(state) {
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return "";
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//var stack = state.b.slice(state.c.SP & 0x1fff, 0x400);
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//return "\n" + dumpRAM(stack, state.c.SP, stack.length);
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}
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}
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PLATFORMS['galaxian'] = GalaxianPlatform;
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