MichaelValwin/Chipvuelto8
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Fixed some quirks of chip8

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This commit is contained in:
Miguel Angel 2024-09-07 01:32:33 +02:00
parent 0b71b99b79
commit 26774f49af
2 changed files with 22 additions and 17 deletions
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6
index.html
View File

@ -82,7 +82,7 @@
emulator.startAudio(audioContext, volume); emulator.startAudio(audioContext, volume);
// Load ROM // Load ROM
fetch(fullDirRoms[3]) fetch(fullDirRoms[4])
.then(response => response.arrayBuffer()) .then(response => response.arrayBuffer())
.then(arrayBufferRom => { .then(arrayBufferRom => {
let romData = new Uint8Array(arrayBufferRom); let romData = new Uint8Array(arrayBufferRom);
@ -93,11 +93,11 @@
setInterval(function() { setInterval(function() {
if(emulator.isRomLoaded()) { if(emulator.isRomLoaded()) {
console.log(emulator.getCPUStatus()); //console.log(emulator.getCPUStatus());
emulator.emulateCycle(); emulator.emulateCycle();
emulator.drawToCanvas(emulatorCanvas, 8); emulator.drawToCanvas(emulatorCanvas, 8);
} }
}, 10); }, 3);
</script> </script>
</body> </body>
</html> </html>

33
src/cpu.ts
View File

@ -228,17 +228,23 @@ class CPU {
}else if(nib4 == 0x1) { }else if(nib4 == 0x1) {
// 8XY1 // 8XY1
// Vx |= Vy // Vx |= Vy
this.regs[nib2] |= this.regs[nib3]; this.regs[nib2] |= this.regs[nib3];
this.regs[0xF] = 0;
this.incrementPC(); this.incrementPC();
}else if(nib4 == 0x2) { }else if(nib4 == 0x2) {
// 8XY2 // 8XY2
// Vx &= Vy // Vx &= Vy
this.regs[nib2] &= this.regs[nib3]; this.regs[nib2] &= this.regs[nib3];
this.regs[0xF] = 0;
this.incrementPC(); this.incrementPC();
}else if(nib4 == 0x3) { }else if(nib4 == 0x3) {
// 8XY3 // 8XY3
// Vx ^= Vy // Vx ^= Vy
this.regs[nib2] ^= this.regs[nib3]; this.regs[nib2] ^= this.regs[nib3];
this.regs[0xF] = 0;
this.incrementPC(); this.incrementPC();
}else if(nib4 == 0x4) { }else if(nib4 == 0x4) {
// 8XY4 // 8XY4
@ -250,23 +256,20 @@ class CPU {
}else if(nib4 == 0x5) { }else if(nib4 == 0x5) {
// 8XY5 // 8XY5
// Vx -= Vy // Vx -= Vy
let subs = 0; let subs = this.regs[nib2] - this.regs[nib3];
if(this.regs[nib2] >= this.regs[nib3]) { let carryBit = this.regs[nib2] >= this.regs[nib3] ? 1 : 0;
subs = this.regs[nib2] - this.regs[nib3];
}else{
subs = this.regs[nib2] - this.regs[nib3];
//subs = 0xFF - subs;
}
this.regs[0xF] = this.regs[nib2] >= this.regs[nib3] ? 1 : 0;
this.regs[nib2] = subs & 0xFF; this.regs[nib2] = subs & 0xFF;
this.regs[0xF] = carryBit;
this.incrementPC(); this.incrementPC();
}else if(nib4 == 0x6) { }else if(nib4 == 0x6) {
// 8XY6 // 8XY6
// Vx >>= 1 // Vx >>= 1
// Stores the least significant bit of VX prior to the shift in VF // Stores the least significant bit of VX prior to the shift in VF
// Then. Shift Vx by 1 to the right. // Then. Shift Vx by 1 to the right.
this.regs[0xF] = this.regs[nib2] & 0x1; // Get the least significat bit let lsb = this.regs[nib2] & 0x01;
this.regs[nib2] = (this.regs[nib2] >> 1) & 0xFF; this.regs[nib2] = this.regs[nib3];
this.regs[nib2] = this.regs[nib2] >> 1;
this.regs[0xF] = lsb;
this.incrementPC(); this.incrementPC();
}else if(nib4 == 0x7) { }else if(nib4 == 0x7) {
// 8XY7 // 8XY7
@ -280,8 +283,10 @@ class CPU {
// Vx <<= 1 // Vx <<= 1
// Set VF to 1 if the most significant bit of VX. // Set VF to 1 if the most significant bit of VX.
// Then shift to the left Vx // Then shift to the left Vx
this.regs[0xF] = (this.regs[nib2]) >> 7; // Get msb let msb = this.regs[nib2] >> 7;
this.regs[nib2] = (this.regs[nib2] << 1) & 0xFF; this.regs[nib2] = this.regs[nib3];
this.regs[nib2] = this.regs[nib2] << 1;
this.regs[0xF] = msb;
this.incrementPC(); this.incrementPC();
} }
@ -431,7 +436,7 @@ class CPU {
// reg_dump(Vx, &I) // reg_dump(Vx, &I)
// Stores from V0 to VX in memory starting at address I. // Stores from V0 to VX in memory starting at address I.
for(let i = 0; i <= nib2; i++) { for(let i = 0; i <= nib2; i++) {
this.memory[this.indexReg + i] = this.regs[i]; this.memory[this.indexReg++] = this.regs[i];
} }
this.incrementPC(); this.incrementPC();
}else if(secondOpcode == 0x65) { }else if(secondOpcode == 0x65) {
@ -439,7 +444,7 @@ class CPU {
// reg_load(Vx, &I) // reg_load(Vx, &I)
// Fills fomr V0 to VX with values from memory staring at address I. // Fills fomr V0 to VX with values from memory staring at address I.
for(let i = 0; i <= nib2; i++) { for(let i = 0; i <= nib2; i++) {
this.regs[i] = this.memory[this.indexReg + i]; this.regs[i] = this.memory[this.indexReg++];
} }
this.incrementPC(); this.incrementPC();
} }