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c64-6502.ts
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c64-6502.ts
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// emu6502.ts - class Emu6502 - MOS6502 Emulator
//
////////////////////////////////////////////////////////////////////////////////
//
// ts-emu-c64
// C64/6502 Emulator for Web Browser
//
// MIT License
//
// Copyright (c) 2020 by David R. Van Wagner
// davevw.com
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
//
////////////////////////////////////////////////////////////////////////////////
let scancodes_queue : string[] = []; // queue of string, each is comma separated list of scan codes
let scancodes_irq : string[] = []; // array of scan codes, used for full IRQ cycle
let basic_rom: number[] = [];
let char_rom: number[] = [];
let kernal_rom: number[] = [];
let redraw_screen: boolean = true;
let attach: Uint8Array = new Uint8Array(0);
let autoexec: boolean = false;
let timerA_enabled: boolean = false;
let timerA_triggered: boolean = false;
interface Memory {
get(i: number): number;
set(i: number, value: number): void;
}
class Emu6502 {
protected memory: Memory;
public breakpoints: number[];
public A: number = 0;
public X: number = 0;
public Y: number = 0;
protected S: number = 0xFF;
protected N: boolean = false;
protected V: boolean = false;
protected B: boolean = true;
protected D: boolean = false;
protected I: boolean = false;
protected Z: boolean = false;
public C: boolean = false;
public PC: number = 0;
protected trace_count: number = 0;
protected trace: boolean = false;
protected step: boolean = false;
protected exit: boolean = false;
protected yield: boolean = false;
public running_tests_disable_IRQ = false;
protected execute: (context: any) => boolean;
protected context: any;
private roms_loaded : boolean = false;
public constructor(memory: Memory, execute: (context: any) => boolean, context: any) {
this.memory = memory;
this.execute = execute;
this.context = context;
this.breakpoints = [];
}
public async ResetRun() {
// wait for ROMs
while (!this.roms_loaded)
{
let missing_roms : boolean = false;
if (kernal_rom.length != 8192)
missing_roms = true;
if (basic_rom.length != 8192)
missing_roms = true;
if (char_rom.length != 4096)
missing_roms = true;
if (missing_roms)
{
console.log("waiting a second for Commodore ROMs...");
await new Promise(r => setTimeout(r, 1000));
}
else
this.roms_loaded = true;
}
let addr: number = (this.memory.get(0xFFFC) | (this.memory.get(0xFFFD) << 8)); // JMP(RESET)
this.Execute(addr);
}
Walk(addrs: number[]) {
var walker = new Walk6502();
if (addrs.length == 0)
walker.Walk(this, this.memory.get(0xFFFC) | (this.memory.get(0xFFFD) << 8));
else {
let i: number;
for (i = 0; i < addrs.length; ++i)
walker.Walk(this, addrs[i]);
}
}
public static toHex(value: number, digits: number): string {
let s: string = value.toString(16).toUpperCase();
while (s.length < digits)
s = "0" + s;
return s;
}
public static toHex8(value: number): string {
return Emu6502.toHex(value, 2);
}
public static toHex16(value: number): string {
return Emu6502.toHex(value, 4);
}
getNextScanCodes()
{
if (scancodes_queue.length > 0) {
let s = scancodes_queue.shift();
if (s==null || s.length == 0)
scancodes_irq = [];
else
scancodes_irq = s.split(',');
}
// else keep same ones going, either still pressed or not pressed
}
isTimerAStarted(): boolean {
let bank = this.memory.get(1);
let reset_bank = false;
let result = true;
if ((bank & 3) == 0 || (bank & 4) == 0) { // check if IO is banked out
reset_bank = true; // remember to restore
this.memory.set(1, 7); // necessary to switch bank to IO
}
result = (this.memory.get(0xDC0E) & 1) == 1; // Control Register A, Timer Started
if (reset_bank)
this.memory.set(1, bank); // need to restore banking state
return result;
}
async Execute(addr: number) {
let conditional: boolean;
let bytes: number;
let interrupt_time = (1 / 60) * 1000; // 60 times per second, converted to milliseconds
let timer_then = Date.now();
let timer2 = timer_then;
this.PC = addr;
while (true) {
while (true) {
let timer_read = Date.now();
let irq = false;
if (!this.running_tests_disable_IRQ && (timer_read - timer_then) >= interrupt_time) // 1/60th of a second
{
if (!this.I) { // if IRQ not disabled
timer_then = timer_read;
this.getNextScanCodes(); // each IRQ gets new buffered scan codes to help guarantee keystrokes get through
if (timerA_enabled && this.isTimerAStarted()) { // timer hardware enabled?
this.Push(this.HI(this.PC));
this.Push(this.LO(this.PC));
let flags: number =
(this.N ? 0x80 : 0)
| (this.V ? 0x40 : 0)
| 0x20 // reserved always set when pushed
| (this.D ? 0x08 : 0)
| (this.I ? 0x04 : 0)
| (this.Z ? 0x02 : 0)
| (this.C ? 0x01 : 0);
this.Push(flags);
this.I = true;
this.PC = this.memory.get(0xFFFE) | (this.memory.get(0xFFFF) << 8);
irq = true;
timer2 = timer_read;
timerA_triggered = true;
}
}
// if (!irq && ((timer_read - timer2))) // yield every 1/60th of a second even if irq didn't happen
// {
// await new Promise(r => setTimeout(r, 0));
// timer2 = timer_read;
// }
}
if (this.exit)
return;
bytes = 1;
let breakpoint: boolean = false;
if (this.breakpoints.indexOf(this.PC) >= 0)
breakpoint = true;
if (this.trace || breakpoint || this.step) {
let addr2: number;
let line: string;
let dis: string;
[dis, conditional, bytes, addr2, line] = this.Disassemble_Long(this.PC);
while (line.length < 30)
line += ' ';
let state: string = this.GetDisplayState();
console.log(line + state);
if (this.step)
debugger;
if (breakpoint)
debugger;
}
if (this.execute != null && !this.execute(this.context)) // allow execute to be overriden at a specific address
break;
}
this.yield = false;
switch (this.memory.get(this.PC)) {
case 0x00: this.BRK(); bytes = 0; break;
case 0x01: this.ORA(this.GetIndX()); bytes = 2; break;
case 0x05: this.ORA(this.GetZP()); bytes = 2; break;
case 0x06: this.SetZP(this.ASL(this.GetZP())); bytes = 2; break;
case 0x08: this.PHP(); break;
case 0x09: this.ORA(this.GetIM()); bytes = 2; break;
case 0x0A: this.SetA(this.ASL(this.A)); break;
case 0x0D: this.ORA(this.GetABS()); bytes = 3; break;
case 0x0E: this.SetABS(this.ASL(this.GetABS())); bytes = 3; break;
case 0x10: this.BPL(); conditional = true; bytes = 0; break;
case 0x11: this.ORA(this.GetIndY()); bytes = 2; break;
case 0x15: this.ORA(this.GetZPX()); bytes = 2; break;
case 0x16: this.SetZPX(this.ASL(this.GetZPX())); bytes = 2; break;
case 0x18: this.CLC(); break;
case 0x19: this.ORA(this.GetABSY()); bytes = 3; break;
case 0x1D: this.ORA(this.GetABSX()); bytes = 3; break;
case 0x1E: this.SetABSX(this.ASL(this.GetABSX())); bytes = 3; break;
case 0x20: this.JSR(); bytes = 0; break;
case 0x21: this.AND(this.GetIndX()); bytes = 2; break;
case 0x24: this.BIT(this.GetZP()); bytes = 2; break;
case 0x25: this.AND(this.GetZP()); bytes = 2; break;
case 0x26: this.SetZP(this.ROL(this.GetZP())); bytes = 2; break;
case 0x28: this.PLP(); break;
case 0x29: this.AND(this.GetIM()); bytes = 2; break;
case 0x2A: this.SetA(this.ROL(this.A)); break;
case 0x2C: this.BIT(this.GetABS()); bytes = 3; break;
case 0x2D: this.AND(this.GetABS()); bytes = 3; break;
case 0x2E: this.SetABS(this.ROL(this.GetABS())); bytes = 3; break;
case 0x30: this.BMI(); conditional = true; bytes = 0; break;
case 0x31: this.AND(this.GetIndY()); bytes = 2; break;
case 0x35: this.AND(this.GetZPX()); bytes = 2; break;
case 0x36: this.SetZPX(this.ROL(this.GetZPX())); bytes = 2; break;
case 0x38: this.SEC(); break;
case 0x39: this.AND(this.GetABSY()); bytes = 3; break;
case 0x3D: this.AND(this.GetABSX()); bytes = 3; break;
case 0x3E: this.SetABSX(this.ROL(this.GetABSX())); bytes = 3; break;
case 0x40: this.RTI(); bytes = 0; break;
case 0x41: this.EOR(this.GetIndX()); bytes = 2; break;
case 0x45: this.EOR(this.GetZP()); bytes = 2; break;
case 0x46: this.SetZP(this.LSR(this.GetZP())); bytes = 2; break;
case 0x48: this.PHA(); break;
case 0x49: this.EOR(this.GetIM()); bytes = 2; break;
case 0x4A: this.SetA(this.LSR(this.A)); break;
case 0x4C: this.JMP(); bytes = 0; break;
case 0x4D: this.EOR(this.GetABS()); bytes = 3; break;
case 0x4E: this.SetABS(this.LSR(this.GetABS())); bytes = 3; break;
case 0x50: this.BVC(); conditional = true; bytes = 0; break;
case 0x51: this.EOR(this.GetIndY()); bytes = 2; break;
case 0x55: this.EOR(this.GetZPX()); bytes = 2; break;
case 0x56: this.SetZPX(this.LSR(this.GetZPX())); bytes = 2; break;
case 0x58: this.CLI(); break;
case 0x59: this.EOR(this.GetABSY()); bytes = 3; break;
case 0x5D: this.EOR(this.GetABSX()); bytes = 3; break;
case 0x5E: this.SetABSX(this.LSR(this.GetABSX())); bytes = 3; break;
case 0x60: this.RTS(); bytes = 0; break;
case 0x61: this.ADC(this.GetIndX()); bytes = 2; break;
case 0x65: this.ADC(this.GetZP()); bytes = 2; break;
case 0x66: this.SetZP(this.ROR(this.GetZP())); bytes = 2; break;
case 0x68: this.PLA(); break;
case 0x69: this.ADC(this.GetIM()); bytes = 2; break;
case 0x6A: this.SetA(this.ROR(this.A)); break;
case 0x6C: this.JMPIND(); bytes = 0; break;
case 0x6D: this.ADC(this.GetABS()); bytes = 3; break;
case 0x6E: this.SetABS(this.ROR(this.GetABS())); bytes = 3; break;
case 0x70: this.BVS(); conditional = true; bytes = 0; break;
case 0x71: this.ADC(this.GetIndY()); bytes = 2; break;
case 0x75: this.ADC(this.GetZPX()); bytes = 2; break;
case 0x76: this.SetZPX(this.ROR(this.GetZPX())); bytes = 2; break;
case 0x78: this.SEI(); break;
case 0x79: this.ADC(this.GetABSY()); bytes = 3; break;
case 0x7D: this.ADC(this.GetABSX()); bytes = 3; break;
case 0x7E: this.SetABSX(this.ROR(this.GetABSX())); bytes = 3; break;
case 0x81: this.SetIndX(this.A); bytes = 2; break;
case 0x84: this.SetZP(this.Y); bytes = 2; break;
case 0x85: this.SetZP(this.A); bytes = 2; break;
case 0x86: this.SetZP(this.X); bytes = 2; break;
case 0x88: this.DEY(); break;
case 0x8A: this.TXA(); break;
case 0x8C: this.SetABS(this.Y); bytes = 3; break;
case 0x8D: this.SetABS(this.A); bytes = 3; break;
case 0x8E: this.SetABS(this.X); bytes = 3; break;
case 0x90: this.BCC(); conditional = true; bytes = 0; break;
case 0x91: this.SetIndY(this.A); bytes = 2; break;
case 0x94: this.SetZPX(this.Y); bytes = 2; break;
case 0x95: this.SetZPX(this.A); bytes = 2; break;
case 0x96: this.SetZPY(this.X); bytes = 2; break;
case 0x98: this.TYA(); break;
case 0x99: this.SetABSY(this.A); bytes = 3; break;
case 0x9A: this.TXS(); break;
case 0x9D: this.SetABSX(this.A); bytes = 3; break;
case 0xA0: this.SetY(this.GetIM()); bytes = 2; break;
case 0xA1: this.SetA(this.GetIndX()); bytes = 2; break;
case 0xA2: this.SetX(this.GetIM()); bytes = 2; break;
case 0xA4: this.SetY(this.GetZP()); bytes = 2; break;
case 0xA5: this.SetA(this.GetZP()); bytes = 2; break;
case 0xA6: this.SetX(this.GetZP()); bytes = 2; break;
case 0xA8: this.TAY(); break;
case 0xA9: this.SetA(this.GetIM()); bytes = 2; break;
case 0xAA: this.TAX(); break;
case 0xAC: this.SetY(this.GetABS()); bytes = 3; break;
case 0xAD: this.SetA(this.GetABS()); bytes = 3; break;
case 0xAE: this.SetX(this.GetABS()); bytes = 3; break;
case 0xB0: this.BCS(); conditional = true; bytes = 0; break;
case 0xB1: this.SetA(this.GetIndY()); bytes = 2; break;
case 0xB4: this.SetY(this.GetZPX()); bytes = 2; break;
case 0xB5: this.SetA(this.GetZPX()); bytes = 2; break;
case 0xB6: this.SetX(this.GetZPY()); bytes = 2; break;
case 0xB8: this.CLV(); break;
case 0xB9: this.SetA(this.GetABSY()); bytes = 3; break;
case 0xBA: this.TSX(); break;
case 0xBC: this.SetY(this.GetABSX()); bytes = 3; break;
case 0xBD: this.SetA(this.GetABSX()); bytes = 3; break;
case 0xBE: this.SetX(this.GetABSY()); bytes = 3; break;
case 0xC0: this.CPY(this.GetIM()); bytes = 2; break;
case 0xC1: this.CMP(this.GetIndX()); bytes = 2; break;
case 0xC4: this.CPY(this.GetZP()); bytes = 2; break;
case 0xC5: this.CMP(this.GetZP()); bytes = 2; break;
case 0xC6: this.SetZP(this.DEC(this.GetZP())); bytes = 2; break;
case 0xC8: this.INY(); break;
case 0xC9: this.CMP(this.GetIM()); bytes = 2; break;
case 0xCA: this.DEX(); break;
case 0xCC: this.CPY(this.GetABS()); bytes = 3; break;
case 0xCD: this.CMP(this.GetABS()); bytes = 3; break;
case 0xCE: this.SetABS(this.DEC(this.GetABS())); bytes = 3; break;
case 0xD0: this.BNE(); conditional = true; bytes = 0; break;
case 0xD1: this.CMP(this.GetIndY()); bytes = 2; break;
case 0xD5: this.CMP(this.GetZPX()); bytes = 2; break;
case 0xD6: this.SetZPX(this.DEC(this.GetZPX())); bytes = 2; break;
case 0xD8: this.CLD(); break;
case 0xD9: this.CMP(this.GetABSY()); bytes = 3; break;
case 0xDD: this.CMP(this.GetABSX()); bytes = 3; break;
case 0xDE: this.SetABSX(this.DEC(this.GetABSX())); bytes = 3; break;
case 0xE0: this.CPX(this.GetIM()); bytes = 2; break;
case 0xE1: this.SBC(this.GetIndX()); bytes = 2; break;
case 0xE4: this.CPX(this.GetZP()); bytes = 2; break;
case 0xE5: this.SBC(this.GetZP()); bytes = 2; break;
case 0xE6: this.SetZP(this.INC(this.GetZP())); bytes = 2; break;
case 0xE8: this.INX(); break;
case 0xE9: this.SBC(this.GetIM()); bytes = 2; break;
case 0xEA: this.NOP(); break;
case 0xEC: this.CPX(this.GetABS()); bytes = 3; break;
case 0xED: this.SBC(this.GetABS()); bytes = 3; break;
case 0xEE: this.SetABS(this.INC(this.GetABS())); bytes = 3; break;
case 0xF0: this.BEQ(); conditional = true; bytes = 0; break;
case 0xF1: this.SBC(this.GetIndY()); bytes = 2; break;
case 0xF5: this.SBC(this.GetZPX()); bytes = 2; break;
case 0xF6: this.SetZPX(this.INC(this.GetZPX())); bytes = 2; break;
case 0xF8: this.SED(); break;
case 0xF9: this.SBC(this.GetABSY()); bytes = 3; break;
case 0xFD: this.SBC(this.GetABSX()); bytes = 3; break;
case 0xFE: this.SetABSX(this.INC(this.GetABSX())); bytes = 3; break;
default:
throw new Error("Invalid opcode " + this.memory.get(this.PC) + " at " + this.PC);
}
this.PC = (this.PC + bytes) & 0xFFFF;
if (this.yield)
await new Promise(r => setTimeout(r, 0));
}
}
// https://javascript.info/task/delay-promise
// async delay(ms : number) {
// return new Promise(resolve => setTimeout(resolve, ms));
// }
CMP(value: number) {
this.Subtract(this.A, value);
}
CPX(value: number) {
this.Subtract(this.X, value);
}
CPY(value: number) {
this.Subtract(this.Y, value);
}
SBC(value: number) {
if (this.D) {
let A_dec: number = (this.A & 0xF) + ((this.A >> 4) * 10);
let value_dec: number = (value & 0xF) + ((value >> 4) * 10);
let result_dec: number = A_dec - value_dec - (this.C ? 0 : 1);
this.C = (result_dec >= 0);
if (!this.C)
result_dec += 100; // adjust for negative result
let result: number = (result_dec % 10) | (((result_dec / 10) % 10) << 4);
this.SetA(result);
this.N = false; // undefined?
this.V = false; // undefined?
}
else {
let overflow: [boolean] = [this.V];
let result: number = this.Subtract(this.A, value, overflow);
this.V = overflow[0];
this.SetA(result);
}
}
Subtract(reg: number, value: number, overflow?: [boolean]) {
if (overflow == null)
this.C = true; // init for CMP, etc.
let old_reg_neg: boolean = (reg & 0x80) != 0;
let value_neg: boolean = (value & 0x80) != 0;
let result: number = reg - value - (this.C ? 0 : 1);
this.N = (result & 0x80) != 0;
this.C = (result >= 0);
this.Z = (result == 0);
let result_neg: boolean = (result & 0x80) != 0;
if (overflow != null)
overflow[0] = (old_reg_neg && !value_neg && !result_neg) // neg - pos = pos
|| (!old_reg_neg && value_neg && result_neg); // pos - neg = neg
return result;
}
ADC(value: number) {
let result: number;
if (this.D) {
let A_dec: number = (this.A & 0xF) + ((this.A >> 4) * 10);
let value_dec: number = (value & 0xF) + ((value >> 4) * 10);
let result_dec: number = A_dec + value_dec + (this.C ? 1 : 0);
this.C = (result_dec > 99);
result = (result_dec % 10) | (((result_dec / 10) % 10) << 4);
this.SetA(result);
this.Z = (result_dec == 0); // BCD quirk -- 100 doesn't set Z
this.V = false;
}
else {
let A_old_neg: boolean = (this.A & 0x80) != 0;
let value_neg: boolean = (value & 0x80) != 0;
let result: number = this.A + value + (this.C ? 1 : 0);
this.C = (result & 0x100) != 0;
this.SetA(result);
let result_neg: boolean = (result & 0x80) != 0;
this.V = (!A_old_neg && !value_neg && result_neg) // pos + pos = neg: overflow
|| (A_old_neg && value_neg && !result_neg); // neg + neg = pos: overflow
}
}
ORA(value: number) {
this.SetA(this.A | value);
}
EOR(value: number) {
this.SetA(this.A ^ value);
}
AND(value: number) {
this.SetA(this.A & value);
}
BIT(value: number) {
this.Z = (this.A & value) == 0;
this.N = (value & 0x80) != 0;
this.V = (value & 0x40) != 0;
}
ASL(value: number) {
this.C = (value & 0x80) != 0;
value = (value << 1) & 0xFF;
this.Z = (value == 0);
this.N = (value & 0x80) != 0;
return value;
}
LSR(value: number) {
this.C = (value & 0x01) != 0;
value = (value >> 1);
this.Z = (value == 0);
this.N = false;
return value;
}
ROL(value: number) {
let newC: boolean = (value & 0x80) != 0;
value = ((value << 1) & 0xFF) | (this.C ? 1 : 0);
this.C = newC;
this.Z = (value == 0);
this.N = (value & 0x80) != 0;
return value;
}
ROR(value: number) {
let newC: boolean = (value & 0x01) != 0;
this.N = this.C;
value = ((value >> 1) | (this.C ? 0x80 : 0));
this.C = newC;
this.Z = (value == 0);
return value;
}
Push(value: number) {
this.memory.set(0x100 | this.S, value);
this.S = (this.S - 1) & 0xFF;
}
Pop() {
this.S = (this.S + 1) & 0xFF;
return this.memory.get(0x100 | this.S);
}
PHP() {
let flags: number =
(this.N ? 0x80 : 0)
| (this.V ? 0x40 : 0)
| 0x20 // reserved always set when pushed
| 0x10 // break always set when pushed
| (this.D ? 0x08 : 0)
| (this.I ? 0x04 : 0)
| (this.Z ? 0x02 : 0)
| (this.C ? 0x01 : 0);
this.Push(flags);
}
PLP() {
let flags: number = this.Pop();
this.N = (flags & 0x80) != 0;
this.V = (flags & 0x40) != 0;
this.B = (flags & 0x10) != 0;
this.D = (flags & 0x08) != 0;
this.I = (flags & 0x04) != 0;
this.Z = (flags & 0x02) != 0;
this.C = (flags & 0x01) != 0;
}
PHA() {
this.Push(this.A);
}
PLA() {
this.SetA(this.Pop());
}
CLC() {
this.C = false;
}
CLD() {
this.D = false;
}
CLI() {
this.I = false;
}
CLV() {
this.V = false;
}
SEC() {
this.C = true;
}
SED() {
this.D = true;
}
SEI() {
this.I = true;
}
INX() {
this.X = this.INC(this.X);
}
INY() {
this.Y = this.INC(this.Y);
}
DEX() {
this.X = this.DEC(this.X);
}
DEY() {
this.Y = this.DEC(this.Y);
}
NOP() {
// do nothing operation
}
DEC(value: number) {
value = (value - 1) & 0xFF;
this.Z = (value == 0);
this.N = (value & 0x80) != 0;
return value;
}
INC(value: number) {
value = (value + 1) & 0xFF;
this.Z = (value == 0);
this.N = (value & 0x80) != 0;
return value;
}
TXA() {
this.A = this.SetReg(this.X);
}
TAX() {
this.X = this.SetReg(this.A);
}
TYA() {
this.A = this.SetReg(this.Y);
}
TAY() {
this.Y = this.SetReg(this.A);
}
TXS() {
this.S = this.X;
}
TSX() {
this.X = this.SetReg(this.S);
}
BR(branch: boolean) {
let addr2: number = this.GetBR();
if (branch)
this.PC = addr2;
else
this.PC = this.IncWord(this.PC+1); // safer +2
}
BPL() {
this.BR(!this.N);
}
BMI() {
this.BR(this.N);
}
BCC() {
this.BR(!this.C);
}
BCS() {
this.BR(this.C);
}
BVC() {
this.BR(!this.V);
}
BVS() {
this.BR(this.V);
}
BNE() {
this.BR(!this.Z);
}
BEQ() {
this.BR(this.Z);
}
JSR() {
let addr2: number = this.IncWord(this.PC+1); // safer than +2
this.Push(this.HI(addr2));
this.Push(this.LO(addr2));
this.PC = this.GetNextWord(this.PC);
}
public RTS() {
let lo: number = this.Pop();
let hi: number = this.Pop();
this.PC = this.IncWord((hi << 8) | lo);
}
RTI() {
this.PLP();
let lo: number = this.Pop();
let hi: number = this.Pop();
this.PC = ((hi << 8) | lo);
}
BRK() {
this.PC = this.IncWord(this.PC);
this.PC = this.IncWord(this.PC);
this.Push(this.HI(this.PC));
this.Push(this.LO(this.PC));
this.PHP();
this.B = true;
this.I = true;
this.PC = this.memory.get(0xFFFE) | (this.memory.get(0xFFFF) << 8); // JMP(IRQ)
}
JMP() {
this.PC = this.GetNextWord(this.PC);
}
JMPIND() {
let addr2: number = this.GetNextWord(this.PC);
if ((addr2 & 0xFF) == 0xFF) // JMP($XXFF) won't go over page boundary
this.PC = (this.memory.get(addr2) | (this.memory.get(addr2 - 0xFF) << 8)); // 6502 "bug" - will use XXFF and XX00 as source of address
else
this.PC = this.memory.get(addr2) | (this.memory.get(addr2+1) << 8); // note: IncWord not necessary 'cause already checked for overflow
}
public SetA(value: number) {
this.A = this.SetReg(value);
}
public SetX(value: number) {
this.X = this.SetReg(value);
}
public SetY(value: number) {
this.Y = this.SetReg(value);
}
SetReg(value: number) {
value = value & 0xFF; // truncate to byte
this.Z = (value == 0);
this.N = ((value & 0x80) != 0);
return value;
}
GetIndX() {
let addr2: number = (this.memory.get(this.IncWord(this.PC)) + this.X) & 0xFF; // compute ZP address using offset
let addr3: number = this.memory.get(addr2) | (this.memory.get((addr2 + 1) & 0xFF) << 8); // stay in ZP
return this.memory.get(addr3);
}
SetIndX(value: number) {
let addr2: number = (this.memory.get(this.IncWord(this.PC)) + this.X) & 0xFF; // compute ZP address using offset
let addr3: number = this.memory.get(addr2) | (this.memory.get((addr2 + 1) & 0xFF) << 8); // stay in ZP
this.memory.set(addr3, value);
}
GetIndY() {
let addr2: number = this.memory.get(this.IncWord(this.PC)); // get ZP address
let addr3: number = (this.memory.get(addr2) | (this.memory.get((addr2 + 1) & 0xFF) << 8)) + this.Y; // keep source in ZP, add offset
return this.memory.get(addr3);
}
SetIndY(value: number) {
let addr2: number = this.memory.get(this.IncWord(this.PC)); // get ZP address
let addr3: number = (this.memory.get(addr2) | (this.memory.get((addr2 + 1) & 0xFF) << 8)) + this.Y; // keep source in ZP, add offset
this.memory.set(addr3, value);
}
GetZP() {
let addr2: number = this.memory.get(this.IncWord(this.PC));
return this.memory.get(addr2);
}
SetZP(value: number) {
let addr2: number = this.memory.get(this.IncWord(this.PC));
this.memory.set(addr2, value);
}
GetZPX() {
let addr2: number = this.memory.get(this.IncWord(this.PC));
return this.memory.get((addr2 + this.X) & 0xFF);
}
SetZPX(value: number) {
let addr2: number = this.memory.get(this.IncWord(this.PC));
this.memory.set((addr2 + this.X) & 0xFF, value);
}
GetZPY() {
let addr2: number = this.memory.get(this.IncWord(this.PC));
return this.memory.get((addr2 + this.Y) & 0xFF);
}
SetZPY(value: number) {
let addr2: number = this.memory.get(this.IncWord(this.PC));
this.memory.set((addr2 + this.Y) & 0xFF, value);
}
GetABS() {
let addr2: number = this.GetNextWord(this.PC);
let value = this.memory.get(addr2);
if (addr2 == 0xDC01) // keyboard scan read
this.yield = true;
return value;
}
SetABS(value: number) {
let addr2: number = this.GetNextWord(this.PC);
this.memory.set(addr2, value);
}
GetABSX() {
let addr2: number = (this.GetNextWord(this.PC) + this.X) & 0xFFFF;
return this.memory.get(addr2);
}
SetABSX(value: number) {
let addr2: number = (this.GetNextWord(this.PC) + this.X) & 0xFFFF;
this.memory.set(addr2, value);
}
GetABSY() {
let addr2: number = (this.GetNextWord(this.PC) + this.Y) & 0xFFFF;
return this.memory.get(addr2);
}
SetABSY(value: number) {
let addr2: number = (this.GetNextWord(this.PC) + this.Y) & 0xFFFF;
this.memory.set(addr2, value);
}
GetIM() {
return this.memory.get(this.IncWord(this.PC));
}
GetBR() {
let offset: number = this.sbyte(this.memory.get(this.IncWord(this.PC)));
return (this.PC + 2 + offset) & 0xFFFF;
}
public sbyte(value: number) {
value &= 0xFF; // force to byte
if (value & 0x80)
return - ((value ^ 0xFF) + 1); // signed byte is negative -128..-1
else
return value; // signed byte is non-negative 0..127
}
IncWord(value: number) {
return (value + 1) & 0xFFFF;
}
protected GetNextWord(addr: number) {
let addr1: number = this.IncWord(addr);
let addr2: number = this.IncWord(addr1);
return (this.memory.get(addr1) | (this.memory.get(addr2) << 8));
}
public LO(value: number) {
return value & 0xFF; // low byte
}
public HI(value: number) {
return (value >> 8) & 0xFF; // high byte
}
GetDisplayState(): string {
return "A:" + Emu6502.toHex8(this.A) +
" X:" + Emu6502.toHex8(this.X) +
" Y:" + Emu6502.toHex8(this.Y) +
" S:" + Emu6502.toHex8(this.S) +
" P:" +
(this.N ? 'N' : ' ') +
(this.V ? 'V' : ' ') +
'-' +
'-' + // B
(this.D ? 'D' : ' ') +
(this.I ? 'I' : ' ') +
(this.Z ? 'Z' : ' ') +
(this.C ? 'C' : ' ');
}
public Disassemble_Long(addr: number): [string, boolean, number, number, string] {
let dis: string;
let conditional: boolean;
let bytes: number;
let addr2: number;
let line: string;
[dis, conditional, bytes, addr2] = this.Disassemble_Short(addr);
let s: string = "";
s += Emu6502.toHex16(addr) + " ";
let i: number;
for (i = 0; i < 3; ++i) {
if (i < bytes)
s += Emu6502.toHex8(this.memory.get(addr + i)) + " ";
else
s += " ";
}
s += dis;
line = s;
return [dis, conditional, bytes, addr2, line];
}
Disassemble_Short(addr: number): [string, boolean, number, number] {
let conditional: boolean = false;
let bytes: number = 1;
let addr2: number = 0;
let dis: string;
switch (this.memory.get(addr)) {
case 0x00: dis = "BRK"; break;
case 0x01: [dis, bytes] = this.DisIndX("ORA", addr); break;
case 0x05: [dis, bytes] = this.DisZP("ORA", addr); break;
case 0x06: [dis, bytes] = this.DisZP("ASL", addr); break;
case 0x08: dis = "PHP"; break;
case 0x09: [dis, bytes] = this.DisIM("ORA", addr); break;
case 0x0A: dis = "ASL A"; break;
case 0x0D: [dis, bytes] = this.DisABS("ORA", addr); break;
case 0x0E: [dis, bytes] = this.DisABS("ASL", addr); break;
case 0x10: [dis, conditional, addr2, bytes] = this.DisBR("BPL", addr); break;
case 0x11: [dis, bytes] = this.DisIndY("ORA", addr); break;
case 0x15: [dis, bytes] = this.DisZPX("ORA", addr); break;
case 0x16: [dis, bytes] = this.DisZPX("ASL", addr); break;
case 0x18: dis = "CLC"; break;
case 0x19: [dis, bytes] = this.DisABSY("ORA", addr); break;
case 0x1D: [dis, bytes] = this.DisABSX("ORA", addr); break;
case 0x1E: [dis, bytes] = this.DisABSX("ASL", addr); break;
case 0x20: [dis, addr2, bytes] = this.DisABSAddr("JSR", addr); break;
case 0x21: [dis, bytes] = this.DisIndX("AND", addr); break;
case 0x24: [dis, bytes] = this.DisZP("BIT", addr); break;
case 0x25: [dis, bytes] = this.DisZP("AND", addr); break;
case 0x26: [dis, bytes] = this.DisZP("ROL", addr); break;
case 0x28: dis = "PLP"; break;
case 0x29: [dis, bytes] = this.DisIM("AND", addr); break;
case 0x2A: dis = "ROL A"; break;
case 0x2C: [dis, bytes] = this.DisABS("BIT", addr); break;
case 0x2D: [dis, bytes] = this.DisABS("AND", addr); break;
case 0x2E: [dis, bytes] = this.DisABS("ROL", addr); break;
case 0x30: [dis, conditional, addr2, bytes] = this.DisBR("BMI", addr); break;
case 0x31: [dis, bytes] = this.DisIndY("AND", addr); break;
case 0x35: [dis, bytes] = this.DisZPX("AND", addr); break;
case 0x36: [dis, bytes] = this.DisZPX("ROL", addr); break;
case 0x38: dis = "SEC"; break;
case 0x39: [dis, bytes] = this.DisABSY("AND", addr); break;
case 0x3D: [dis, bytes] = this.DisABSX("AND", addr); break;
case 0x3E: [dis, bytes] = this.DisABSX("ROL", addr); break;
case 0x40: dis = "RTI"; break;
case 0x41: [dis, bytes] = this.DisIndX("EOR", addr); break;
case 0x45: [dis, bytes] = this.DisZP("EOR", addr); break;
case 0x46: [dis, bytes] = this.DisZP("LSR", addr); break;
case 0x48: dis = "PHA"; break;
case 0x49: [dis, bytes] = this.DisIM("EOR", addr); break;
case 0x4A: dis = "LSR A"; break;
case 0x4C: [dis, addr2, bytes] = this.DisABSAddr("JMP", addr); break;
case 0x4D: [dis, bytes] = this.DisABS("EOR", addr); break;
case 0x4E: [dis, bytes] = this.DisABS("LSR", addr); break;
case 0x50: [dis, conditional, addr2, bytes] = this.DisBR("BVC", addr); break;
case 0x51: [dis, bytes] = this.DisIndY("EOR", addr); break;
case 0x55: [dis, bytes] = this.DisZPX("EOR", addr); break;
case 0x56: [dis, bytes] = this.DisZPX("LSR", addr); break;
case 0x58: dis = "CLI"; break;
case 0x59: [dis, bytes] = this.DisABSY("EOR", addr); break;
case 0x5D: [dis, bytes] = this.DisABSX("EOR", addr); break;
case 0x5E: [dis, bytes] = this.DisABSX("LSR", addr); break;
case 0x60: dis = "RTS"; break;
case 0x61: [dis, bytes] = this.DisIndX("ADC", addr); break;
case 0x65: [dis, bytes] = this.DisZP("ADC", addr); break;