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function NES() {
this.opts = {
preferredFrameRate: 60,
fpsInterval: 500, // Time between updating FPS in ms
showDisplay: true,
emulateSound: false,
sampleRate: 44100, // Sound sample rate in hz
CPU_FREQ_NTSC: 1789772.5,//1789772.72727272d;
CPU_FREQ_PAL: 1773447.4,
}
this.frameTime = 1000/this.opts.preferredFrameRate;
this.cpu = new NES.CPU(this);
this.ppu = new NES.PPU(this);
this.papu = new NES.PAPU(this);
this.mmap = null; // set in loadRom()
this.keyboard = new NES.Keyboard();
$("#status").text("Initialised. Ready to load a ROM.");
}
NES.prototype = {
isRunning: false,
fpsFrameCount: 0,
limitFrames: true,
romData: null,
// Resets the system.
reset: function() {
if(this.mmap != null) {
this.mmap.reset();
}
this.cpu.reset();
this.ppu.reset();
this.papu.reset();
},
start: function() {
var self = this;
if(this.rom != null && this.rom.valid) {
if (!this.isRunning) {
this.isRunning = true;
this.frameInterval = setInterval(function() {
self.frame();
}, this.frameTime/2);
this.resetFps();
this.printFps();
this.fpsInterval = setInterval(function() {
self.printFps();
}, this.opts.fpsInterval);
}
}
else {
alert("There is no ROM loaded, or it is invalid.");
}
},
frame: function() {
this.ppu.startFrame();
var cycles = 0;
var emulateSound = nes.opts.emulateSound;
var cpu = this.cpu;
var ppu = this.ppu;
var papu = this.papu;
FRAMELOOP: for (;;) {
if (cpu.cyclesToHalt == 0) {
// Execute a CPU instruction
cycles = cpu.emulate();
if (emulateSound) {
papu.clockFrameCounter(cycles);
}
cycles *= 3;
}
else {
if (cpu.cyclesToHalt > 8) {
cycles = 24;
if (emulateSound) {
papu.clockFrameCounter(8);
}
cpu.cyclesToHalt -= 8;
}
else {
cycles = cpu.cyclesToHalt * 3;
if (emulateSound) {
papu.clockFrameCounter(cpu.cyclesToHalt);
}
cpu.cyclesToHalt = 0;
}
}
for(;cycles>0;cycles--){
if(ppu.curX == ppu.spr0HitX
&& ppu.f_spVisibility==1
&& ppu.scanline-21 == ppu.spr0HitY){
// Set sprite 0 hit flag:
ppu.setStatusFlag(ppu.STATUS_SPRITE0HIT,true);
}
if(ppu.requestEndFrame){
ppu.nmiCounter--;
if(ppu.nmiCounter == 0){
ppu.requestEndFrame = false;
ppu.startVBlank();
break FRAMELOOP;
}
}
ppu.curX++;
if(ppu.curX==341){
ppu.curX = 0;
ppu.endScanline();
}
}
}
if (this.limitFrames) {
if (this.lastFrameTime) {
while ((new Date()).getTime() - this.lastFrameTime < this.frameTime) {
// twiddle thumbs
}
}
}
this.fpsFrameCount++;
this.lastFrameTime = (new Date()).getTime();
},
printFps: function() {
var now = (new Date()).getTime();
var s = 'Running';
if (this.lastFpsTime) {
s += ': '+(this.fpsFrameCount/((now-this.lastFpsTime)/1000)).toFixed(2)+' FPS';
}
$("#status").text(s);
this.fpsFrameCount = 0;
this.lastFpsTime = now;
},
stop: function() {
//$("#status").text("Stopped.");
clearInterval(this.frameInterval);
clearInterval(this.fpsInterval);
this.isRunning = false;
},
reloadRom: function() {
if(this.romData != null){
this.loadRom(this.romData);
}
},
// Loads a ROM file into the CPU and PPU.
// The ROM file is validated first.
loadRom: function(data) {
if (this.isRunning) {
this.stop();
}
$("#status").text("Loading...");
// Load ROM file:
this.rom = new NES.ROM(this);
this.rom.load(data);
if (this.rom.valid) {
this.reset();
this.mmap = this.rom.createMapper();
if (!this.mmap) {
return;
}
this.mmap.loadROM();
this.ppu.setMirroring(this.rom.getMirroringType());
this.romData = data;
$("#status").text("Successfully loaded. Ready to be started.");
}
else {
$("#status").text("Invalid ROM!");
}
return this.rom.valid;
},
resetFps: function() {
this.lastFpsTime = null;
this.fpsFrameCount = 0;
},
setFramerate: function(rate){
this.nes.opts.preferredFrameRate = rate;
this.nes.frameTime = 1000/rate;
papu.setSampleRate(this.opts.sampleRate, false);
},
setLimitFrames: function(limit) {
this.limitFrames = limit;
this.lastFrameTime = null;
}
}
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