apple2js/js/cpu6502.js

1638 lines
46 KiB
JavaScript

/*
* Copyright 2010-2019 Will Scullin <scullin@scullinsteel.com>
*
* Permission to use, copy, modify, distribute, and sell this software and its
* documentation for any purpose is hereby granted without fee, provided that
* the above copyright notice appear in all copies and that both that
* copyright notice and this permission notice appear in supporting
* documentation. No representations are made about the suitability of this
* software for any purpose. It is provided "as is" without express or
* implied warranty.
*/
import { debug, toHex } from './util';
export default function CPU6502(options)
{
options = options || {};
var is65C02 = options['65C02'] ? true : false;
/* Registers */
var pc = 0, // Program Counter
sr = 0x20, // Process Status Register
ar = 0, // Accumulator
xr = 0, // X Register
yr = 0, // Y Register
sp = 0xff; // Stack Pointer
/* Addressing Mode */
var modes = {
accumulator: 0, // A (Accumulator)
implied: 1, // Implied
immediate: 2, // # Immediate
absolute: 3, // a Absolute
zeroPage: 4, // zp Zero Page
relative: 5, // r Relative
absoluteX: 6, // a,X Absolute, X
absoluteY: 7, // a,Y Absolute, Y
zeroPageX: 8, // zp,X Zero Page, X
zeroPageY: 9, // zp,Y Zero Page, Y
absoluteIndirect: 10, // (a) Indirect
zeroPageXIndirect: 11, // (zp,X) Zero Page Indexed Indirect
zeroPageIndirectY: 12, // (zp),Y Zero Page Indexed with Y
/* 65c02 */
zeroPageIndirect: 13, // (zp),
absoluteXIndirect: 14, // (a, X),
zeroPage_relative: 15 // zp, Relative
};
var sizes = {
0 /* modes.accumulator */: 1,
1 /* modes.implied */: 1,
2 /* modes.immediate */: 2,
3 /* modes.absolute */: 3,
4 /* modes.zeroPage */: 2,
5 /* modes.relative */: 2,
6 /* modes.absoluteX */: 3,
7 /* modes.absoluteY */: 3,
8 /* modes.zeroPageX */: 2,
9 /* modes.zeroPageY */: 2,
10 /* modes.indirect */: 3,
11 /* modes.zeroPageXIndirect */: 2,
12 /* modes.zeroPageYIndirect */: 2,
13 /* mode.zeroPageIndirect */: 2,
14 /* mode.absoluteXIndirect */: 3,
15 /* mode.zeroPage_relative */: 3
};
/* Flags */
var flags = {
N: 0x80, // Negative
V: 0x40, // oVerflow
B: 0x10, // Break
D: 0x08, // Decimal
I: 0x04, // Interrupt
Z: 0x02, // Zero
C: 0x01 // Carry
};
/* Memory Locations */
var loc = {
STACK: 0x100,
NMI: 0xFFFA,
RESET: 0xFFFC,
BRK: 0xFFFE
};
var idx;
var readPages = [];
var writePages = [];
var resetHandlers = [];
var cycles = 0;
var sync = false;
var blankPage = {
read: function() { return 0; },
write: function() {}
};
for (idx = 0; idx < 0x100; idx++) {
readPages[idx] = blankPage;
writePages[idx] = blankPage;
}
function setFlag(f, on) {
sr = on ? (sr | f) : (sr & ~f);
}
function testNZ(val) {
sr = val === 0 ? (sr | flags.Z) : (sr & ~flags.Z);
sr = (val & 0x80) ? (sr | flags.N) : (sr & ~flags.N);
return val;
}
function testZ(val) {
sr = val === 0 ? (sr | flags.Z) : (sr & ~flags.Z);
return val;
}
function add(a, b, sub) {
if (sub)
b ^= 0xff;
// KEGS
var c, v;
if ((sr & flags.D) !== 0) {
c = (a & 0x0f) + (b & 0x0f) + (sr & flags.C);
if (sub) {
if (c < 0x10)
c = (c - 0x06) & 0x0f;
c += (a & 0xf0) + (b & 0xf0);
v = (c >> 1) ^ c;
if (c < 0x100)
c = (c + 0xa0) & 0xff;
} else {
if (c > 0x09)
c = (c - 0x0a) | 0x10; // carry to MSN
c += (a & 0xf0) + (b & 0xf0);
v = (c >> 1) ^ c;
if (c > 0x99)
c += 0x60;
}
} else {
c = a + b + (sr & flags.C);
v = (c ^ a) & 0x80;
}
if (((a ^ b) & 0x80) !== 0) {
v = 0;
}
setFlag(flags.C, c > 0xff);
setFlag(flags.V, v);
return testNZ(c & 0xff);
}
function increment(a) {
return testNZ((a + 0x01) & 0xff);
}
function decrement(a) {
return testNZ((a + 0xff) & 0xff);
}
function readBytePC() {
var addr = pc,
page = addr >> 8,
off = addr & 0xff;
var result = readPages[page].read(page, off);
pc = (pc + 1) & 0xffff;
cycles++;
return result;
}
function readByte(addr) {
var page = addr >> 8,
off = addr & 0xff;
var result = readPages[page].read(page, off);
cycles++;
return result;
}
function readByteDebug(addr) {
var page = addr >> 8,
off = addr & 0xff;
return readPages[page].read(page, off);
}
function writeByte(addr, val) {
var page = addr >> 8,
off = addr & 0xff;
writePages[page].write(page, off, val);
cycles++;
}
function readWord(addr) {
return readByte(addr) | (readByte(addr + 1) << 8);
}
function readWordDebug(addr) {
return readByteDebug(addr) | (readByteDebug(addr + 1) << 8);
}
function readWordPC() {
return readBytePC() | (readBytePC() << 8);
}
function readZPWord(addr) {
var lsb, msb;
lsb = readByte(addr & 0xff);
msb = readByte((addr + 1) & 0xff);
return (msb << 8) | lsb;
}
function pushByte(val) {
writeByte(loc.STACK | sp, val);
sp = (sp + 0xff) & 0xff;
}
function pushWord(val) {
pushByte(val >> 8);
pushByte(val & 0xff);
}
function pullByte() {
sp = (sp + 0x01) & 0xff;
return readByte(loc.STACK | sp);
}
function pullWordRaw() {
var lsb = pullByte(loc.STACK | sp);
var msb = pullByte(loc.STACK | sp);
return (msb << 8) | lsb;
}
/*
* Read functions
*/
function readImplied() {
}
// #$00
function readImmediate() {
return readBytePC();
}
// $0000
function readAbsolute() {
return readByte(readWordPC());
}
// $00
function readZeroPage() {
return readByte(readBytePC());
}
// $0000,X
function readAbsoluteX() {
var addr = readWordPC();
var oldPage = addr >> 8;
addr = (addr + xr) & 0xffff;
var newPage = addr >> 8;
if (newPage != oldPage) {
var off = addr & 0xff;
readByte(oldPage << 8 | off);
}
return readByte(addr);
}
// $0000,Y
function readAbsoluteY() {
var addr = readWordPC();
var oldPage = addr >> 8;
addr = (addr + yr) & 0xffff;
var newPage = addr >> 8;
if (newPage != oldPage) {
var off = addr & 0xff;
readByte(oldPage << 8 | off);
}
return readByte(addr);
}
// $00,X
function readZeroPageX() {
var zpAddr = readBytePC();
readByte(zpAddr);
return readByte((zpAddr + xr) & 0xff);
}
// $00,Y
function readZeroPageY() {
var zpAddr = readBytePC();
readByte(zpAddr);
return readByte((zpAddr + yr) & 0xff);
}
// ($00,X)
function readZeroPageXIndirect() {
var zpAddr = readBytePC();
readByte(zpAddr);
var addr = readZPWord((zpAddr + xr) & 0xff);
return readByte(addr);
}
// ($00),Y
function readZeroPageIndirectY() {
var addr = readZPWord(readBytePC());
var oldPage = addr >> 8;
addr = (addr + yr) & 0xffff;
var newPage = addr >> 8;
if (newPage != oldPage) {
var off = addr & 0xff;
readByte(oldPage << 8 | off);
}
return readByte(addr);
}
// ($00) (65C02)
function readZeroPageIndirect() {
return readByte(readZPWord(readBytePC()));
}
/*
* Write Functions
*/
// $0000
function writeAbsolute(val) {
writeByte(readWordPC(), val);
}
// $00
function writeZeroPage(val) {
writeByte(readBytePC(), val);
}
// $0000,X
function writeAbsoluteX(val) {
var addr = readWordPC(), oldPage = addr >> 8;
addr = (addr + xr) & 0xffff;
var off = addr & 0xff;
readByte(oldPage << 8 | off);
writeByte(addr, val);
}
// $0000,Y
function writeAbsoluteY(val) {
var addr = readWordPC(), oldPage = addr >> 8;
addr = (addr + yr) & 0xffff;
var off = addr & 0xff;
readByte(oldPage << 8 | off);
writeByte(addr, val);
}
// $00,X
function writeZeroPageX(val) {
var zpAddr = readBytePC();
readByte(zpAddr);
writeByte((zpAddr + xr) & 0xff, val);
}
// $00,Y
function writeZeroPageY(val) {
var zpAddr = readBytePC();
readByte(zpAddr);
writeByte((zpAddr + yr) & 0xff, val);
}
// ($00,X)
function writeZeroPageXIndirect(val) {
var zpAddr = readBytePC();
readByte(zpAddr);
var addr = readZPWord((zpAddr + xr) & 0xff);
writeByte(addr, val);
}
// ($00),Y
function writeZeroPageIndirectY(val) {
var addr = readZPWord(readBytePC()), oldPage = addr >> 8;
addr = (addr + yr) & 0xffff;
var off = addr & 0xff;
readByte(oldPage << 8 | off);
writeByte(addr, val);
}
// ($00) (65C02)
function writeZeroPageIndirect(val) {
writeByte(readZPWord(readBytePC()), val);
}
// $00
function readAddrZeroPage() {
return readBytePC();
}
// $00,X
function readAddrZeroPageX() {
var zpAddr = readBytePC();
readByte(zpAddr);
return (zpAddr + xr) & 0xff;
}
// $0000 (65C02)
function readAddrAbsolute() {
return readWordPC();
}
// ($0000) (6502)
function readAddrAbsoluteIndirectBug() {
var addr = readWordPC();
var page = addr & 0xff00;
var off = addr & 0x00ff;
var lsb = readByte(addr);
var msb = readByte(page | ((off + 0x01) & 0xff));
return msb << 8 | lsb;
}
// ($0000) (65C02)
function readAddrAbsoluteIndirect() {
var lsb = readBytePC();
var msb = readBytePC();
readByte(pc);
return readWord(msb << 8 | lsb);
}
// $0000,X
function readAddrAbsoluteX(opts) {
var addr = readWordPC();
if (!is65C02 || (opts && opts.rwm)) {
readByte(addr);
} else {
readByte(pc);
}
return (addr + xr) & 0xffff;
}
// $(0000,X) (65C02)
function readAddrAbsoluteXIndirect() {
var address = readWordPC();
readByte(pc);
return readWord((address + xr) & 0xffff);
}
/* Break */
function brk(readFn) {
readFn();
pushWord(pc);
pushByte(sr | flags.B);
if (is65C02) {
setFlag(flags.D, false);
}
setFlag(flags.I, true);
pc = readWord(loc.BRK);
}
/* Load Accumulator */
function lda(readFn) {
ar = testNZ(readFn());
}
/* Load X Register */
function ldx(readFn) {
xr = testNZ(readFn());
}
/* Load Y Register */
function ldy(readFn) {
yr = testNZ(readFn());
}
/* Store Accumulator */
function sta(writeFn) {
writeFn(ar);
}
/* Store X Register */
function stx(writeFn) {
writeFn(xr);
}
/* Store Y Register */
function sty(writeFn) {
writeFn(yr);
}
/* Store Zero */
function stz(writeFn) {
writeFn(0);
}
/* Add with Carry */
function adc(readFn) {
ar = add(ar, readFn(), false);
}
/* Subtract with Carry */
function sbc(readFn) {
ar = add(ar, readFn(), true);
}
/* Increment Memory */
function incA() {
readByte(pc);
ar = increment(ar);
}
function inc(readAddrFn) {
var addr = readAddrFn({rwm: true});
var oldVal = readByte(addr);
writeByte(addr, oldVal);
var val = increment(oldVal);
writeByte(addr, val);
}
/* Increment X */
function inx() {
readByte(pc);
xr = increment(xr);
}
/* Increment Y */
function iny() {
readByte(pc);
yr = increment(yr);
}
/* Decrement Memory */
function decA() {
readByte(pc);
ar = decrement(ar);
}
function dec(readAddrFn) {
var addr = readAddrFn({rwm: true});
var oldVal = readByte(addr);
writeByte(addr, oldVal);
var val = decrement(oldVal);
writeByte(addr, val);
}
/* Decrement X */
function dex() {
readByte(pc);
xr = decrement(xr);
}
/* Decrement Y */
function dey() {
readByte(pc);
yr = decrement(yr);
}
function shiftLeft(val) {
setFlag(flags.C, val & 0x80);
return testNZ((val << 1) & 0xff);
}
/* Arithmetic Shift Left */
function aslA() {
readByte(pc);
ar = shiftLeft(ar);
}
function asl(readAddrFn) {
var addr = readAddrFn({rwm: true});
var oldVal = readByte(addr);
writeByte(addr, oldVal);
var val = shiftLeft(oldVal);
writeByte(addr, val);
}
function shiftRight(val) {
setFlag(flags.C, val & 0x01);
return testNZ(val >> 1);
}
/* Logical Shift Right */
function lsrA() {
readByte(pc);
ar = shiftRight(ar);
}
function lsr(readAddrFn) {
var addr = readAddrFn({rwm: true});
var oldVal = readByte(addr);
writeByte(addr, oldVal);
var val = shiftRight(oldVal);
writeByte(addr, val);
}
function rotateLeft(val) {
var c = (sr & flags.C);
setFlag(flags.C, val & 0x80);
return testNZ(((val << 1) | (c ? 0x01 : 0x00)) & 0xff);
}
/* Rotate Left */
function rolA() {
readByte(pc);
ar = rotateLeft(ar);
}
function rol(readAddrFn) {
var addr = readAddrFn({rwm: true});
var oldVal = readByte(addr);
writeByte(addr, oldVal);
var val = rotateLeft(oldVal);
writeByte(addr, val);
}
function rotateRight(a) {
var c = (sr & flags.C);
setFlag(flags.C, a & 0x01);
return testNZ((a >> 1) | (c ? 0x80 : 0x00));
}
/* Rotate Right */
function rorA() {
readByte(pc);
ar = rotateRight(ar);
}
function ror(readAddrFn) {
var addr = readAddrFn({rwm: true});
var oldVal = readByte(addr);
writeByte(addr, oldVal);
var val = rotateRight(oldVal);
writeByte(addr, val);
}
/* Logical And Accumulator */
function and(readFn) {
ar = testNZ(ar & readFn());
}
/* Logical Or Accumulator */
function ora(readFn) {
ar = testNZ(ar | readFn());
}
/* Logical Exclusive Or Accumulator */
function eor(readFn) {
ar = testNZ(ar ^ readFn());
}
/* Reset Bit */
function rmb(b) {
var bit = (0x1 << b) ^ 0xFF;
var addr = readBytePC();
var val = readByte(addr);
readByte(addr);
val &= bit;
writeByte(addr, val);
}
/* Set Bit */
function smb(b) {
var bit = 0x1 << b;
var addr = readBytePC();
var val = readByte(addr);
readByte(addr);
val |= bit;
writeByte(addr, val);
}
/* Test and Reset Bits */
function trb(readAddrFn) {
var addr = readAddrFn();
var val = readByte(addr);
testZ(val & ar);
readByte(addr);
writeByte(addr, val & ~ar);
}
/* Test and Set Bits */
function tsb(readAddrFn) {
var addr = readAddrFn();
var val = readByte(addr);
testZ(val & ar);
readByte(addr);
writeByte(addr, val | ar);
}
/* Bit */
function bit(readFn) {
var val = readFn();
setFlag(flags.Z, (val & ar) === 0);
setFlag(flags.N, val & 0x80);
setFlag(flags.V, val & 0x40);
}
/* Bit Immediate*/
function bitI(readFn) {
var val = readFn();
setFlag(flags.Z, (val & ar) === 0);
}
function compare(a, b)
{
b = (b ^ 0xff);
var c = a + b + 1;
setFlag(flags.C, c > 0xff);
testNZ(c & 0xff);
}
function cmp(readFn) {
compare(ar, readFn());
}
function cpx(readFn) {
compare(xr, readFn());
}
function cpy(readFn) {
compare(yr, readFn());
}
/* Branches */
function brs(f) {
var off = readBytePC(); // changes pc
if ((f & sr) !== 0) {
readByte(pc);
var oldPage = pc >> 8;
pc += off > 127 ? off - 256 : off;
var newPage = pc >> 8;
var newOff = pc & 0xff;
if (newPage != oldPage) readByte(oldPage << 8 | newOff);
}
}
function brc(f) {
var off = readBytePC(); // changes pc
if ((f & sr) === 0) {
readByte(pc);
var oldPage = pc >> 8;
pc += off > 127 ? off - 256 : off;
var newPage = pc >> 8;
var newOff = pc & 0xff;
if (newPage != oldPage) readByte(oldPage << 8 | newOff);
}
}
/* WDC 65C02 branches */
function bbr(b) {
var zpAddr = readBytePC();
var val = readByte(zpAddr);
readByte(zpAddr);
var off = readBytePC(); // changes pc
if (((1 << b) & val) === 0) {
var oldPc = pc;
var oldPage = oldPc >> 8;
readByte(oldPc);
pc += off > 127 ? off - 256 : off;
var newPage = pc >> 8;
if (oldPage != newPage) {
readByte(oldPc);
}
}
}
function bbs(b) {
var zpAddr = readBytePC();
var val = readByte(zpAddr);
readByte(zpAddr);
var off = readBytePC(); // changes pc
if (((1 << b) & val) !== 0) {
var oldPc = pc;
var oldPage = oldPc >> 8;
readByte(oldPc);
pc += off > 127 ? off - 256 : off;
var newPage = pc >> 8;
if (oldPage != newPage) {
readByte(oldPc);
}
}
}
/* Transfers and stack */
function tax() { readByte(pc); testNZ(xr = ar); }
function txa() { readByte(pc); testNZ(ar = xr); }
function tay() { readByte(pc); testNZ(yr = ar); }
function tya() { readByte(pc); testNZ(ar = yr); }
function tsx() { readByte(pc); testNZ(xr = sp); }
function txs() { readByte(pc); sp = xr; }
function pha() { readByte(pc); pushByte(ar); }
function pla() { readByte(pc); readByte(0x0100 | sp); testNZ(ar = pullByte()); }
function phx() { readByte(pc); pushByte(xr); }
function plx() { readByte(pc); readByte(0x0100 | sp);testNZ(xr = pullByte()); }
function phy() { readByte(pc); pushByte(yr); }
function ply() { readByte(pc); readByte(0x0100 | sp); testNZ(yr = pullByte()); }
function php() { readByte(pc); pushByte(sr | flags.B); }
function plp() { readByte(pc); readByte(0x0100 | sp); sr = (pullByte() & ~flags.B) | 0x20; }
/* Jump */
function jmp(readAddrFn) {
pc = readAddrFn();
}
/* Jump Subroutine */
function jsr() {
var lsb = readBytePC();
readByte(0x0100 | sp);
pushWord(pc);
var msb = readBytePC();
pc = (msb << 8 | lsb) & 0xffff;
}
/* Return from Subroutine */
function rts() {
readByte(pc);
readByte(0x0100 | sp);
var addr = pullWordRaw();
readByte(addr);
pc = (addr + 1) & 0xffff;
}
/* Return from Subroutine */
function rti() {
readByte(pc);
readByte(0x0100 | sp);
sr = pullByte() & ~flags.B;
pc = pullWordRaw();
}
/* Set and Clear */
function set(flag) {
readByte(pc);
sr |= flag;
}
function clr(flag) {
readByte(pc);
sr &= ~flag;
}
/* No-Op */
function nop(readAddrFn) {
readByte(pc);
readAddrFn();
}
var ops = {
// LDA
0xa9: ['LDA', lda, readImmediate, modes.immediate, 2],
0xa5: ['LDA', lda, readZeroPage, modes.zeroPage, 3],
0xb5: ['LDA', lda, readZeroPageX, modes.zeroPageX, 4],
0xad: ['LDA', lda, readAbsolute, modes.absolute, 4],
0xbd: ['LDA', lda, readAbsoluteX, modes.absoluteX, 4],
0xb9: ['LDA', lda, readAbsoluteY, modes.absoluteY, 4],
0xa1: ['LDA', lda, readZeroPageXIndirect, modes.zeroPageXIndirect, 6],
0xb1: ['LDA', lda, readZeroPageIndirectY, modes.zeroPageIndirectY, 5],
// LDX
0xa2: ['LDX', ldx, readImmediate, modes.immediate, 2],
0xa6: ['LDX', ldx, readZeroPage, modes.zeroPage, 3],
0xb6: ['LDX', ldx, readZeroPageY, modes.zeroPageY, 4],
0xae: ['LDX', ldx, readAbsolute, modes.absolute, 4],
0xbe: ['LDX', ldx, readAbsoluteY, modes.absoluteY, 4],
// LDY
0xa0: ['LDY', ldy, readImmediate, modes.immediate, 2],
0xa4: ['LDY', ldy, readZeroPage, modes.zeroPage, 3],
0xb4: ['LDY', ldy, readZeroPageX, modes.zeroPageX, 4],
0xac: ['LDY', ldy, readAbsolute, modes.absolute, 4],
0xbc: ['LDY', ldy, readAbsoluteX, modes.absoluteX, 4],
// STA
0x85: ['STA', sta, writeZeroPage, modes.zeroPage, 3],
0x95: ['STA', sta, writeZeroPageX, modes.zeroPageX, 4],
0x8d: ['STA', sta, writeAbsolute, modes.absolute, 4],
0x9d: ['STA', sta, writeAbsoluteX, modes.absoluteX, 5],
0x99: ['STA', sta, writeAbsoluteY, modes.absoluteY, 5],
0x81: ['STA', sta, writeZeroPageXIndirect, modes.zeroPageXIndirect, 6],
0x91: ['STA', sta, writeZeroPageIndirectY, modes.zeroPageIndirectY, 6],
// STX
0x86: ['STX', stx, writeZeroPage, modes.zeroPage, 3],
0x96: ['STX', stx, writeZeroPageY, modes.zeroPageY, 4],
0x8e: ['STX', stx, writeAbsolute, modes.absolute, 4],
// STY
0x84: ['STY', sty, writeZeroPage, modes.zeroPage, 3],
0x94: ['STY', sty, writeZeroPageX, modes.zeroPageX, 4],
0x8c: ['STY', sty, writeAbsolute, modes.absolute, 4],
// ADC
0x69: ['ADC', adc, readImmediate, modes.immediate, 2],
0x65: ['ADC', adc, readZeroPage, modes.zeroPage, 3],
0x75: ['ADC', adc, readZeroPageX, modes.zeroPageX, 4],
0x6D: ['ADC', adc, readAbsolute, modes.absolute, 4],
0x7D: ['ADC', adc, readAbsoluteX, modes.absoluteX, 4],
0x79: ['ADC', adc, readAbsoluteY, modes.absoluteY, 4],
0x61: ['ADC', adc, readZeroPageXIndirect, modes.zeroPageXIndirect, 6],
0x71: ['ADC', adc, readZeroPageIndirectY, modes.zeroPageIndirectY, 5],
// SBC
0xe9: ['SBC', sbc, readImmediate, modes.immediate, 2],
0xe5: ['SBC', sbc, readZeroPage, modes.zeroPage, 3],
0xf5: ['SBC', sbc, readZeroPageX, modes.zeroPageX, 4],
0xeD: ['SBC', sbc, readAbsolute, modes.absolute, 4],
0xfD: ['SBC', sbc, readAbsoluteX, modes.absoluteX, 4],
0xf9: ['SBC', sbc, readAbsoluteY, modes.absoluteY, 4],
0xe1: ['SBC', sbc, readZeroPageXIndirect, modes.zeroPageXIndirect, 6],
0xf1: ['SBC', sbc, readZeroPageIndirectY, modes.zeroPageIndirectY, 5],
// INC
0xe6: ['INC', inc, readAddrZeroPage, modes.zeroPage, 5],
0xf6: ['INC', inc, readAddrZeroPageX, modes.zeroPageX, 6],
0xee: ['INC', inc, readAddrAbsolute, modes.absolute, 6],
0xfe: ['INC', inc, readAddrAbsoluteX, modes.absoluteX, 7],
// INX
0xe8: ['INX', inx, null, modes.implied, 2],
// INY
0xc8: ['INY', iny, null, modes.implied, 2],
// DEC
0xc6: ['DEC', dec, readAddrZeroPage, modes.zeroPage, 5],
0xd6: ['DEC', dec, readAddrZeroPageX, modes.zeroPageX, 6],
0xce: ['DEC', dec, readAddrAbsolute, modes.absolute, 6],
0xde: ['DEC', dec, readAddrAbsoluteX, modes.absoluteX, 7],
// DEX
0xca: ['DEX', dex, null, modes.implied, 2],
// DEY
0x88: ['DEY', dey, null, modes.implied, 2],
// ASL
0x0A: ['ASL', aslA, null, modes.accumulator, 2],
0x06: ['ASL', asl, readAddrZeroPage, modes.zeroPage, 5],
0x16: ['ASL', asl, readAddrZeroPageX, modes.zeroPageX, 6],
0x0E: ['ASL', asl, readAddrAbsolute, modes.absolute, 6],
0x1E: ['ASL', asl, readAddrAbsoluteX, modes.absoluteX, 7],
// LSR
0x4A: ['LSR', lsrA, null, modes.accumulator, 2],
0x46: ['LSR', lsr, readAddrZeroPage, modes.zeroPage, 5],
0x56: ['LSR', lsr, readAddrZeroPageX, modes.zeroPageX, 6],
0x4E: ['LSR', lsr, readAddrAbsolute, modes.absolute, 6],
0x5E: ['LSR', lsr, readAddrAbsoluteX, modes.absoluteX, 7],
// ROL
0x2A: ['ROL', rolA, null, modes.accumulator, 2],
0x26: ['ROL', rol, readAddrZeroPage, modes.zeroPage, 5],
0x36: ['ROL', rol, readAddrZeroPageX, modes.zeroPageX, 6],
0x2E: ['ROL', rol, readAddrAbsolute, modes.absolute, 6],
0x3E: ['ROL', rol, readAddrAbsoluteX, modes.absoluteX, 7],
// ROR
0x6A: ['ROR', rorA, null, modes.accumulator, 2],
0x66: ['ROR', ror, readAddrZeroPage, modes.zeroPage, 5],
0x76: ['ROR', ror, readAddrZeroPageX, modes.zeroPageX, 6],
0x6E: ['ROR', ror, readAddrAbsolute, modes.absolute, 6],
0x7E: ['ROR', ror, readAddrAbsoluteX, modes.absoluteX, 7],
// AND
0x29: ['AND', and, readImmediate, modes.immediate, 2],
0x25: ['AND', and, readZeroPage, modes.zeroPage, 3],
0x35: ['AND', and, readZeroPageX, modes.zeroPageX, 4],
0x2D: ['AND', and, readAbsolute, modes.absolute, 4],
0x3D: ['AND', and, readAbsoluteX, modes.absoluteX, 4],
0x39: ['AND', and, readAbsoluteY, modes.absoluteY, 4],
0x21: ['AND', and, readZeroPageXIndirect, modes.zeroPageXIndirect, 6],
0x31: ['AND', and, readZeroPageIndirectY, modes.zeroPageIndirectY, 5],
// ORA
0x09: ['ORA', ora, readImmediate, modes.immediate, 2],
0x05: ['ORA', ora, readZeroPage, modes.zeroPage, 3],
0x15: ['ORA', ora, readZeroPageX, modes.zeroPageX, 4],
0x0D: ['ORA', ora, readAbsolute, modes.absolute, 4],
0x1D: ['ORA', ora, readAbsoluteX, modes.absoluteX, 4],
0x19: ['ORA', ora, readAbsoluteY, modes.absoluteY, 4],
0x01: ['ORA', ora, readZeroPageXIndirect, modes.zeroPageXIndirect, 6],
0x11: ['ORA', ora, readZeroPageIndirectY, modes.zeroPageIndirectY, 5],
// EOR
0x49: ['EOR', eor, readImmediate, modes.immediate, 2],
0x45: ['EOR', eor, readZeroPage, modes.zeroPage, 3],
0x55: ['EOR', eor, readZeroPageX, modes.zeroPageX, 4],
0x4D: ['EOR', eor, readAbsolute, modes.absolute, 4],
0x5D: ['EOR', eor, readAbsoluteX, modes.absoluteX, 4],
0x59: ['EOR', eor, readAbsoluteY, modes.absoluteY, 4],
0x41: ['EOR', eor, readZeroPageXIndirect, modes.zeroPageXIndirect, 6],
0x51: ['EOR', eor, readZeroPageIndirectY, modes.zeroPageIndirectY, 5],
// CMP
0xc9: ['CMP', cmp, readImmediate, modes.immediate, 2],
0xc5: ['CMP', cmp, readZeroPage, modes.zeroPage, 3],
0xd5: ['CMP', cmp, readZeroPageX, modes.zeroPageX, 4],
0xcD: ['CMP', cmp, readAbsolute, modes.absolute, 4],
0xdD: ['CMP', cmp, readAbsoluteX, modes.absoluteX, 4],
0xd9: ['CMP', cmp, readAbsoluteY, modes.absoluteY, 4],
0xc1: ['CMP', cmp, readZeroPageXIndirect, modes.zeroPageXIndirect, 6],
0xd1: ['CMP', cmp, readZeroPageIndirectY, modes.zeroPageIndirectY, 5],
// CPX
0xE0: ['CPX', cpx, readImmediate, modes.immediate, 2],
0xE4: ['CPX', cpx, readZeroPage, modes.zeroPage, 3],
0xEC: ['CPX', cpx, readAbsolute, modes.absolute, 4],
// CPY
0xC0: ['CPY', cpy, readImmediate, modes.immediate, 2],
0xC4: ['CPY', cpy, readZeroPage, modes.zeroPage, 3],
0xCC: ['CPY', cpy, readAbsolute, modes.absolute, 4],
// BIT
0x24: ['BIT', bit, readZeroPage, modes.zeroPage, 3],
0x2C: ['BIT', bit, readAbsolute, modes.absolute, 4],
// BCC
0x90: ['BCC', brc, flags.C, modes.relative, 2],
// BCS
0xB0: ['BCS', brs, flags.C, modes.relative, 2],
// BEQ
0xF0: ['BEQ', brs, flags.Z, modes.relative, 2],
// BMI
0x30: ['BMI', brs, flags.N, modes.relative, 2],
// BNE
0xD0: ['BNE', brc, flags.Z, modes.relative, 2],
// BPL
0x10: ['BPL', brc, flags.N, modes.relative, 2],
// BVC
0x50: ['BVC', brc, flags.V, modes.relative, 2],
// BVS
0x70: ['BVS', brs, flags.V, modes.relative, 2],
// TAX
0xAA: ['TAX', tax, null, modes.implied, 2],
// TXA
0x8A: ['TXA', txa, null, modes.implied, 2],
// TAY
0xA8: ['TAY', tay, null, modes.implied, 2],
// TYA
0x98: ['TYA', tya, null, modes.implied, 2],
// TSX
0xBA: ['TSX', tsx, null, modes.implied, 2],
// TXS
0x9A: ['TXS', txs, null, modes.implied, 2],
// PHA
0x48: ['PHA', pha, null, modes.implied, 3],
// PLA
0x68: ['PLA', pla, null, modes.implied, 4],
// PHP
0x08: ['PHP', php, null, modes.implied, 3],
// PLP
0x28: ['PLP', plp, null, modes.implied, 4],
// JMP
0x4C: [
'JMP', jmp, readAddrAbsolute, modes.absolute, 3
],
0x6C: [
'JMP', jmp, readAddrAbsoluteIndirectBug, modes.absoluteIndirect, 5
],
// JSR
0x20: ['JSR', jsr, readAddrAbsolute, modes.absolute, 6],
// RTS
0x60: ['RTS', rts, null, modes.implied, 6],
// RTI
0x40: ['RTI', rti, null, modes.implied, 6],
// SEC
0x38: ['SEC', set, flags.C, modes.implied, 2],
// SED
0xF8: ['SED', set, flags.D, modes.implied, 2],
// SEI
0x78: ['SEI', set, flags.I, modes.implied, 2],
// CLC
0x18: ['CLC', clr, flags.C, modes.implied, 2],
// CLD
0xD8: ['CLD', clr, flags.D, modes.implied, 2],
// CLI
0x58: ['CLI', clr, flags.I, modes.implied, 2],
// CLV
0xB8: ['CLV', clr, flags.V, modes.implied, 2],
// NOP
0xea: ['NOP', nop, readImplied, modes.implied, 2],
// BRK
0x00: ['BRK', brk, readImmediate, modes.immediate, 7]
};
/* 65C02 Instructions */
var cops = {
// INC / DEC A
0x1A: ['INC', incA, null, modes.accumulator, 2],
0x3A: ['DEC', decA, null, modes.accumulator, 2],
// Indirect Zero Page for the masses
0x12: ['ORA', ora, readZeroPageIndirect, modes.zeroPageIndirect, 5],
0x32: ['AND', and, readZeroPageIndirect, modes.zeroPageIndirect, 5],
0x52: ['EOR', eor, readZeroPageIndirect, modes.zeroPageIndirect, 5],
0x72: ['ADC', adc, readZeroPageIndirect, modes.zeroPageIndirect, 5],
0x92: ['STA', sta, writeZeroPageIndirect, modes.zeroPageIndirect, 5],
0xB2: ['LDA', lda, readZeroPageIndirect, modes.zeroPageIndirect, 5],
0xD2: ['CMP', cmp, readZeroPageIndirect, modes.zeroPageIndirect, 5],
0xF2: ['SBC', sbc, readZeroPageIndirect, modes.zeroPageIndirect, 5],
// Better BIT
0x34: ['BIT', bit, readZeroPageX, modes.zeroPageX, 4],
0x3C: ['BIT', bit, readAbsoluteX, modes.absoluteX, 4],
0x89: ['BIT', bitI, readImmediate, modes.immediate, 2],
// JMP absolute indirect indexed
0x6C: [
'JMP', jmp, readAddrAbsoluteIndirect, modes.absoluteIndirect, 6
],
0x7C: [
'JMP', jmp, readAddrAbsoluteXIndirect, modes.absoluteXIndirect, 6
],
// BBR/BBS
0x0F: ['BBR0', bbr, 0, modes.zeroPage_relative, 5],
0x1F: ['BBR1', bbr, 1, modes.zeroPage_relative, 5],
0x2F: ['BBR2', bbr, 2, modes.zeroPage_relative, 5],
0x3F: ['BBR3', bbr, 3, modes.zeroPage_relative, 5],
0x4F: ['BBR4', bbr, 4, modes.zeroPage_relative, 5],
0x5F: ['BBR5', bbr, 5, modes.zeroPage_relative, 5],
0x6F: ['BBR6', bbr, 6, modes.zeroPage_relative, 5],
0x7F: ['BBR7', bbr, 7, modes.zeroPage_relative, 5],
0x8F: ['BBS0', bbs, 0, modes.zeroPage_relative, 5],
0x9F: ['BBS1', bbs, 1, modes.zeroPage_relative, 5],
0xAF: ['BBS2', bbs, 2, modes.zeroPage_relative, 5],
0xBF: ['BBS3', bbs, 3, modes.zeroPage_relative, 5],
0xCF: ['BBS4', bbs, 4, modes.zeroPage_relative, 5],
0xDF: ['BBS5', bbs, 5, modes.zeroPage_relative, 5],
0xEF: ['BBS6', bbs, 6, modes.zeroPage_relative, 5],
0xFF: ['BBS7', bbs, 7, modes.zeroPage_relative, 5],
// BRA
0x80: ['BRA', brc, 0, modes.relative, 2],
// NOP
0x02: ['NOP', nop, readImmediate, modes.immediate, 2],
0x22: ['NOP', nop, readImmediate, modes.immediate, 2],
0x42: ['NOP', nop, readImmediate, modes.immediate, 2],
0x44: ['NOP', nop, readImmediate, modes.immediate, 3],
0x54: ['NOP', nop, readImmediate, modes.immediate, 4],
0x62: ['NOP', nop, readImmediate, modes.immediate, 2],
0x82: ['NOP', nop, readImmediate, modes.immediate, 2],
0xC2: ['NOP', nop, readImmediate, modes.immediate, 2],
0xD4: ['NOP', nop, readImmediate, modes.immediate, 4],
0xE2: ['NOP', nop, readImmediate, modes.immediate, 2],
0xF4: ['NOP', nop, readImmediate, modes.immediate, 4],
0x5C: ['NOP', nop, readAbsolute, modes.absolute, 8],
0xDC: ['NOP', nop, readAbsolute, modes.absolute, 4],
0xFC: ['NOP', nop, readAbsolute, modes.absolute, 4],
// PHX
0xDA: ['PHX', phx, null, modes.implied, 3],
// PHY
0x5A: ['PHY', phy, null, modes.implied, 3],
// PLX
0xFA: ['PLX', plx, null, modes.implied, 4],
// PLY
0x7A: ['PLY', ply, null, modes.implied, 4],
// RMB/SMB
0x07: ['RMB0', rmb, 0, modes.zeroPage, 5],
0x17: ['RMB1', rmb, 1, modes.zeroPage, 5],
0x27: ['RMB2', rmb, 2, modes.zeroPage, 5],
0x37: ['RMB3', rmb, 3, modes.zeroPage, 5],
0x47: ['RMB4', rmb, 4, modes.zeroPage, 5],
0x57: ['RMB5', rmb, 5, modes.zeroPage, 5],
0x67: ['RMB6', rmb, 6, modes.zeroPage, 5],
0x77: ['RMB7', rmb, 7, modes.zeroPage, 5],
0x87: ['SMB0', smb, 0, modes.zeroPage, 5],
0x97: ['SMB1', smb, 1, modes.zeroPage, 5],
0xA7: ['SMB2', smb, 2, modes.zeroPage, 5],
0xB7: ['SMB3', smb, 3, modes.zeroPage, 5],
0xC7: ['SMB4', smb, 4, modes.zeroPage, 5],
0xD7: ['SMB5', smb, 5, modes.zeroPage, 5],
0xE7: ['SMB6', smb, 6, modes.zeroPage, 5],
0xF7: ['SMB7', smb, 7, modes.zeroPage, 5],
// STZ
0x64: ['STZ', stz, writeZeroPage, modes.zeroPage, 3],
0x74: ['STZ', stz, writeZeroPageX, modes.zeroPageX, 4],
0x9C: ['STZ', stz, writeAbsolute, modes.absolute, 4],
0x9E: ['STZ', stz, writeAbsoluteX, modes.absoluteX, 5],
// TRB
0x14: ['TRB', trb, readAddrZeroPage, modes.zeroPage, 5],
0x1C: ['TRB', trb, readAddrAbsolute, modes.absolute, 6],
// TSB
0x04: ['TSB', tsb, readAddrZeroPage, modes.zeroPage, 5],
0x0C: ['TSB', tsb, readAddrAbsolute, modes.absolute, 6]
};
if (is65C02) {
for (var key in cops) {
if (cops.hasOwnProperty(key)) {
ops[key] = cops[key];
}
}
}
function unknown(b) {
var unk;
if (is65C02) {
unk = [
'NOP',
nop,
readImplied,
modes.implied,
2
];
} else {
unk = [
'???',
function() {
debug('Unknown OpCode: ' + toHex(b) +
' at ' + toHex(pc - 1, 4));
},
readImplied,
modes.implied,
1
];
}
ops[b] = unk;
return unk;
}
/* Certain browsers benefit from using arrays over maps */
var opary = [];
for (idx = 0; idx < 0x100; idx++) {
opary[idx] = ops[idx] || unknown(idx);
}
function dumpArgs(addr, m, symbols) {
var val;
var off;
function toHexOrSymbol(v, n) {
if (symbols && symbols[v]) {
return symbols[v];
} else {
return '$' + toHex(v, n);
}
}
var result = '';
switch (m) {
case modes.implied:
break;
case modes.immediate:
result = '#' + toHexOrSymbol(readByteDebug(addr));
break;
case modes.absolute:
result = '' + toHexOrSymbol(readWordDebug(addr), 4);
break;
case modes.zeroPage:
result = '' + toHexOrSymbol(readByteDebug(addr));
break;
case modes.relative:
{
off = readByteDebug(addr);
if (off > 127) {
off -= 256;
}
addr += off + 1;
result = '' + toHexOrSymbol(addr, 4) + ' (' + off + ')';
}
break;
case modes.absoluteX:
result = '' + toHexOrSymbol(readWordDebug(addr), 4) + ',X';
break;
case modes.absoluteY:
result = '' + toHexOrSymbol(readWordDebug(addr), 4) + ',Y';
break;
case modes.zeroPageX:
result = '' + toHexOrSymbol(readByteDebug(addr)) + ',X';
break;
case modes.zeroPageY:
result = '' + toHexOrSymbol(readByteDebug(addr)) + ',Y';
break;
case modes.absoluteIndirect:
result = '(' + toHexOrSymbol(readWordDebug(addr), 4) + ')';
break;
case modes.zeroPageXIndirect:
result = '(' + toHexOrSymbol(readByteDebug(addr)) + ',X)';
break;
case modes.zeroPageIndirectY:
result = '(' + toHexOrSymbol(readByteDebug(addr)) + '),Y';
break;
case modes.accumulator:
result = 'A';
break;
case modes.zeroPageIndirect:
result = '(' + toHexOrSymbol(readByteDebug(addr)) + ')';
break;
case modes.absoluteXIndirect:
result = '(' + toHexOrSymbol(readWordDebug(addr), 4) + ',X)';
break;
case modes.zeroPage_relative:
val = readByteDebug(addr);
off = readByteDebug(addr + 1);
if (off > 127) {
off -= 256;
}
addr += off + 2;
result = '' + toHexOrSymbol(val) + ',' + toHexOrSymbol(addr, 4) + ' (' + off + ')';
break;
default:
break;
}
return result;
}
return {
step: function cpu_step(cb) {
sync = true;
var op = opary[readBytePC()];
sync = false;
op[1](op[2]);
if (cb) {
cb(this);
}
},
stepDebug: function(n, cb) {
var op, idx;
for (idx = 0; idx < n; idx++) {
sync = true;
op = opary[readBytePC()];
sync = false;
op[1](op[2]);
if (cb) {
cb(this);
}
}
},
stepCycles: function(c) {
var op, end = cycles + c;
while (cycles < end) {
sync = true;
op = opary[readBytePC()];
sync = false;
op[1](op[2]);
}
},
stepCyclesDebug: function(c, cb)
{
var op, end = cycles + c;
while (cycles < end) {
sync = true;
op = opary[readBytePC()];
sync = false;
op[1](op[2]);
if (cb) {
cb(this);
}
}
},
addPageHandler: function(pho) {
for (var idx = pho.start(); idx <= pho.end(); idx++) {
if (pho.read)
readPages[idx] = pho;
if (pho.write)
writePages[idx] = pho;
}
if (pho.reset)
resetHandlers.push(pho);
},
reset: function cpu_reset()
{
// cycles = 0;
sr = 0x20;
sp = 0xff;
ar = 0;
yr = 0;
xr = 0;
pc = readWord(loc.RESET);
for (var idx = 0; idx < resetHandlers.length; idx++) {
resetHandlers[idx].reset();
}
},
/* IRQ - Interrupt Request */
irq: function cpu_irq()
{
if ((sr & flags.I) === 0) {
pushWord(pc);
pushByte(sr & ~flags.B);
if (is65C02) {
setFlag(flags.D, false);
}
setFlag(flags.I, true);
pc = readWord(loc.BRK);
}
},
/* NMI Non-maskable Interrupt */
nmi: function cpu_nmi()
{
pushWord(pc);
pushByte(sr & ~flags.B);
if (is65C02) {
setFlag(flags.D, false);
}
setFlag(flags.I, true);
pc = readWord(loc.NMI);
},
getPC: function () {
return pc;
},
setPC: function(_pc) {
pc = _pc;
},
dumpPC: function(_pc, symbols) {
if (_pc === undefined) {
_pc = pc;
}
var b = readByte(_pc, true),
op = ops[b],
size = sizes[op[3]],
result = toHex(_pc, 4) + '- ';
if (symbols) {
if (symbols[_pc]) {
result += symbols[_pc] +
' '.substring(symbols[_pc].length);
} else {
result += ' ';
}
}
for (var idx = 0; idx < 4; idx++) {
if (idx < size) {
result += toHex(readByte(_pc + idx, true)) + ' ';
} else {
result += ' ';
}
}
if (op === undefined)
result += '??? (' + toHex(b) + ')';
else
result += op[0] + ' ' + dumpArgs(_pc + 1, op[3], symbols);
return result;
},
dumpPage: function(start, end) {
var result = '';
if (start === undefined) {
start = pc >> 8;
}
if (end === undefined) {
end = start;
}
for (var page = start; page <= end; page++) {
var b, idx, jdx;
for (idx = 0; idx < 16; idx++) {
result += toHex(page) + toHex(idx << 4) + ': ';
for (jdx = 0; jdx < 16; jdx++) {
b = readByteDebug(page * 256 + idx * 16 + jdx);
result += toHex(b) + ' ';
}
result += ' ';
for (jdx = 0; jdx < 16; jdx++) {
b = readByte(page * 256 + idx * 16 + jdx, true) & 0x7f;
if (b >= 0x20 && b < 0x7f) {
result += String.fromCharCode(b);
} else {
result += '.';
}
}
result += '\n';
}
}
return result;
},
list: function(_pc, symbols) {
if (_pc === undefined) {
_pc = pc;
}
var results = [];
for (var jdx = 0; jdx < 20; jdx++) {
var b = readByte(_pc), op = ops[b];
results.push(this.dumpPC(_pc, symbols));
_pc += sizes[op[3]];
}
return results;
},
sync: function() {
return sync;
},
cycles: function() {
return cycles;
},
registers: function() {
return [pc,ar,xr,yr,sr,sp];
},
getState: function() {
return {
a: ar,
x: xr,
y: yr,
s: sr,
pc: pc,
sp: sp,
cycles: cycles
};
},
setState: function(state) {
ar = state.a;
xr = state.x;
yr = state.y;
sr = state.s;
pc = state.pc;
sp = state.sp;
cycles = state.cycles;
},
dumpRegisters: function() {
return toHex(pc, 4) +
'- A=' + toHex(ar) +
' X=' + toHex(xr) +
' Y=' + toHex(yr) +
' P=' + toHex(sr) +
' S=' + toHex(sp) +
' ' +
((sr & flags.N) ? 'N' : '-') +
((sr & flags.V) ? 'V' : '-') +
'-' +
((sr & flags.B) ? 'B' : '-') +
((sr & flags.D) ? 'D' : '-') +
((sr & flags.I) ? 'I' : '-') +
((sr & flags.Z) ? 'Z' : '-') +
((sr & flags.C) ? 'C' : '-');
},
read: function(page, off) {
return readPages[page].read(page, off);
},
write: function(page, off, val) {
writePages[page].write(page, off, val);
}
};
}