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GSjs
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GSjs/cpu.js

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function StatusRegister() {
this.N = false; // bit 7: Negative flag
this.V = false; // bit 6: oVerflow flag
this.R = true; // bit 5: Reserved flag: hardwired to '1'
this.B = false; // bit 4: Break flag
this.D = false; // bit 3: Decimal flag
this.I = false; // bit 2: Interrupt flag
this.Z = false; // bit 1: Zero flag
this.C = false; // bit 0: Carry flag
}
StatusRegister.prototype.get = function() {
return (this.N<<7) + (this.V<<6) + 32 + (this.B<<4) +
(this.D<<3) + (this.I<<2) + (this.Z<<1) + this.C;
};
StatusRegister.prototype.set= function(value) {
this.N = (value & (1<<7)) > 0;
this.V = (value & (1<<6)) > 0;
this.B = (value & (1<<4)) > 0;
this.D = (value & (1<<3)) > 0;
this.I = (value & (1<<2)) > 0;
this.Z = (value & (1<<1)) > 0;
this.C = (value & 1) > 0;
};
function Cpu(memCtrl) {
// Simulates connections to the IRQ and NMI pins. If set to true (HIGH), then
// IRQ or NMI interrupts will be triggered
this.irq_pin = false;
this.nmi_pin = false;
// Interrupt vector addresses; these are hardwired in the CPU
var VECTOR_NMI = 0xFFFA; // non-maskable interrupt
var VECTOR_RST = 0xFFFC; // reset
var VECTOR_IRQ = 0xFFFE; // interrupt request
// Registers
var regA = 0x00; // Accumulator
var regX = 0x00; // X-index register
var regY = 0x00; // Y-index register
var regSP = 0xFF; // Stack pointer
var regPC = 0x00; // Program counter
regSR = new StatusRegister(); // Status register
// State information
var cycle = 0; // CPU cycle counter
var opcode = 0x00; // current opcode
var PCinc = 0x00; // amount to increase PC at end of cycle
var waiting = false; // CPU waiting (due to WAI)
var stopped = false; // CPU halted (due to STP)
// Helper functions
function operandAddr() { // Address of LSB of operand
return (regPC + 1) & 0xFFFF;
}
function updateNZ(data) { // Update the N and Z flags
regSR.Z = (data === 0); // Z flag true if data == 0
regSR.N = (data & 0x80) > 0; // N flag true if bit 7 = 1;
}
function pushStack(data) { // Push data onto stack
var addr = (0x01 << 8) | regSP;
memCtrl.setData(addr, data);
regSP = (regSP - 1) & 0xFF;
}
function pullStack() { // Pull data from stack
regSP = (regSP + 1) & 0xFF;
var addr = (0x01 << 8) | regSP;
return memCtrl.getData(addr);
}
function pushStackAddr(addr) { // Push 16-bit address onto stack
pushStack((addr & 0xFF00) >> 8); // push high byte
pushStack(addr & 0x00FF); // push low byte
}
function pullStackAddr() { // Pull 16-bit address from stack
var lo = pullStack(); // pull low byte
var hi = pullStack(); // pull high byte
return lo + (hi << 8);
}
function checkBranch(addr, condition) { // check if we can do a branch
if (condition) {
// do the branch
cycle++;
if ((regPC & 0xFF00) != (addr & 0xFF00))
cycle++; // add a cycle if PB crossed
regPC = addr;
}
}
// Cycle lookup table
var opcycles =
[7, 6, 2, 1, 5, 3, 5, 5, 3, 2, 2, 1, 6, 4, 6, 5,
2, 5, 5, 1, 5, 4, 6, 5, 2, 4, 2, 1, 6, 4, 6, 5,
6, 6, 2, 1, 3, 3, 5, 5, 4, 2, 2, 1, 4, 4, 6, 5,
2, 5, 5, 1, 4, 4, 6, 5, 2, 4, 2, 1, 4, 4, 6, 5,
6, 6, 2, 1, 3, 3, 5, 5, 3, 2, 2, 1, 3, 4, 6, 5,
2, 5, 5, 1, 4, 4, 6, 5, 2, 4, 3, 1, 8, 4, 6, 5,
6, 6, 2, 1, 3, 3, 5, 5, 4, 2, 2, 1, 6, 4, 6, 5,
2, 5, 5, 1, 4, 4, 6, 5, 2, 4, 4, 1, 6, 4, 6, 5,
3, 6, 2, 1, 3, 3, 3, 5, 2, 2, 2, 1, 4, 4, 4, 5,
2, 6, 5, 1, 4, 4, 4, 5, 2, 5, 2, 1, 4, 5, 5, 5,
2, 6, 2, 1, 3, 3, 3, 5, 2, 2, 2, 1, 4, 4, 4, 5,
2, 5, 5, 1, 4, 4, 4, 5, 2, 4, 2, 1, 4, 4, 4, 5,
2, 6, 2, 1, 3, 3, 5, 5, 2, 2, 2, 3, 4, 4, 6, 5,
2, 5, 5, 1, 4, 4, 6, 5, 2, 4, 3, 3, 4, 4, 7, 5,
2, 6, 2, 1, 3, 3, 5, 5, 2, 2, 2, 1, 4, 4, 6, 5,
2, 5, 5, 1, 4, 4, 6, 5, 2, 4, 4, 1, 4, 4, 7, 5];
/** Implicit addressing
* Address is implicit in operand
* e.g. RTS
* 0 bytes
*/
var amImplicit = function() {
return regPC;
};
/** Accumulator addressing
* Use accumulator for data
* e.g. ASL A
* 0 bytes
*/
var amAccumulator = function() {
return regPC;
};
/** Immediate Mode addressing
* Address immediately follows opcode
* e.g. LDA #$65
* 1 byte
*/
var amImmediate = function() {
PCinc++;
return (regPC + 1) & 0xFFFF;
};
/** Zero Page addressing
* Zero page address is formed by taking next 8-bit value
* e.g. LDA $4F
* 1 byte
*/
var amZeroPage = function() {
PCinc++;
return memCtrl.getData(operandAddr());
};
/** Zero Page, X addressing
* Zero page address is formed by taking next 8-bit value and
* adding X to it. Address wraps around page $00
* e.g. LDA $65,X
* 1 byte
*/
var amZeroPageX = function() {
PCinc++;
return (memCtrl.getData(operandAddr()) + regX) & 0x00FF;
};
/** Zero Page, Y addressing
* Zero page address is formed by taking next 8-bit value and
* adding Y to it. Address wraps around page $00
* e.g. LDA $5C,Y
* 1 byte
*/
var amZeroPageY = function() {
PCinc++;
return (memCtrl.getData(operandAddr()) + regY) & 0x00FF;
};
/** Zero Page Indirect addressing
* Address is formed by taking zero page address from next 8-bit value
* Zero page location is LSB of 16-bit address. Wrap around occurs.
* e.g. LDA ($23)
* 1 byte
*/
var amZPIndirect = function() {
PCinc++;
var addr = memCtrl.getData(operandAddr());
return memCtrl.getData(addr) + (memCtrl.getData(addr+1 & 0x00FF) << 8);
};
/** Zero Page Indirect, X addressing
* Address is formed by taking zero page address from next 8-bit value
* and adding X to it (with wrap around).
* Zero page location is LSB of 16-bit address. Wrap around occurs.
* e.g. LDA ($D2,X)
* 1 byte
*/
var amZPIndirectX = function() {
PCinc++;
var addr = (memCtrl.getData(operandAddr()) + regX) & 0x00FF;
return memCtrl.getData(addr) + (memCtrl.getData(addr+1 & 0x00FF) << 8);
};
/** Zero Page Indirect, Y addressing
* Address is formed by taking zero page address from next 8-bit value
* Zero page location is LSB of 16-bit address. Y is added to this value
* e.g. LDA ($C1),Y
* 1 byte, +1 cycle if PB crossed
*/
var amZPIndirectY = function() {
PCinc++;
var zp_addr = memCtrl.getData(operandAddr());
var ind_addr = memCtrl.getData(zp_addr) + (memCtrl.getData((zp_addr+1) & 0x00FF) << 8);
var addr = (ind_addr + regY) & 0xFFFF;
// check if PB is crossed
if ((addr & 0xFF00) != (ind_addr & 0xFF00)) { cycle++; }
return addr;
};
/** Zero Page Relative addressing
* Zero page address is given by the next 8-bit value, and the 8-bit value
* that follows is a signed offset (-128 -> +127)
* e.g. BBR0 $23,12
* 2 bytes
*/
var amZPRelative = function() {
PCinc += 2;
return memCtrl.getData(operandAddr());
};
/** Relative addressing
* Signed offset (-128 -> +127) is given by the next 8-bit value
* e.g. BEQ -34
* 1 byte
*/
var amRelative = function() {
PCinc++;
var offset = memCtrl.getData(operandAddr());
if (offset > 127) {
return (regPC + (offset - 256)) & 0xFFFF;
} else {
return (regPC + offset) & 0xFFFF;
}
};
/** Absolute addressing
* Located at address pointed to by next 16-bit memory value
* e.g. JMP $872F
* 2 bytes
*/
var amAbsolute = function() {
PCinc += 2;
return memCtrl.getAddr(operandAddr());
};
/** Absolute, X addressing
* Address is formed by taking next 16-bit memory value, and
* adding X to it
* e.g. JMP $1291,X
* 2 bytes, +1 cycle if PB crossed
*/
var amAbsoluteX = function() {
PCinc += 2;
var base_addr = memCtrl.getAddr(operandAddr());
var addr = (base_addr + regX) & 0xFFFF;
// check if PB is crossed (except for DEC and INC - new for 65C02)
if (((addr & 0xFF00) != (base_addr & 0xFF00)) &&
(opcode != 0xDE && 0xFE)) { cycle++; }
return addr;
};
/** Absolute, Y addressing
* Address is formed by taking next 16-bit memory value, and
* adding Y to it
* e.g. JMP $C123,Y
* 2 bytes, +1 cycle if PB crossed
*/
var amAbsoluteY = function() {
PCinc += 2;
var base_addr = memCtrl.getAddr(operandAddr());
var addr = (base_addr + regY) & 0xFFFF;
// check if PB is crossed
if ((addr & 0xFF00) != (base_addr & 0xFF00)) { cycle++; }
return addr;
};
/** Absolute Indirect addressing
* Next 16-bits are the address of another address
* e.g. JMP ($4C21)
* 2 bytes
*/
var amIndirect = function() {
PCinc += 2;
var addr = memCtrl.getAddr(operandAddr());
return memCtrl.getAddr(addr);
};
/** Absolute Indirect Indexed addressing
* Next 16-bits are added to X, which point to another address
* e.g. JMP ($0823,X)
* 2 bytes
*/
var amAbsIndIndx = function() {
PCinc += 2; cycle += 5;
var addr = (memCtrl.getAddr(operandAddr()) + regX) & 0xFFFF;
return memCtrl.getAddr(addr);
};
// Opcode functions
var opLDA = function(amFn) { regA = memCtrl.getData(amFn()); updateNZ(regA); };
var opLDX = function(amFn) { regX = memCtrl.getData(amFn()); updateNZ(regX); };
var opLDY = function(amFn) { regY = memCtrl.getData(amFn()); updateNZ(regY); };
var opSTA = function(amFn) { memCtrl.setData(amFn(), regA); };
var opSTX = function(amFn) { memCtrl.setData(amFn(), regX); };
var opSTY = function(amFn) { memCtrl.setData(amFn(), regY); };
var opSTZ = function(amFn) { memCtrl.setData(amFn(), 0x00); };
var opPHA = function(amFn) { pushStack(regA); };
var opPHX = function(amFn) { pushStack(regX); };
var opPHY = function(amFn) { pushStack(regY); };
var opPHP = function(amFn) { regSR.B = true; pushStack(regSR.get()); };
var opPLA = function(amFn) { regA = pullStack(); updateNZ(regA); };
var opPLX = function(amFn) { regX = pullStack(); updateNZ(regX); };
var opPLY = function(amFn) { regY = pullStack(); updateNZ(regY); };
var opPLP = function(amFn) { regSR.set(pullStack()); regSR.B = true; };
var opTSX = function(amFn) { regX = regSP; updateNZ(regX); };
var opTXS = function(amFn) { regSP = regX; };
var opINA = function(amFn) { regA = (regA+1) & 0xFF; updateNZ(regA); };
var opINX = function(amFn) { regX = (regX+1) & 0xFF; updateNZ(regX); };
var opINY = function(amFn) { regY = (regY+1) & 0xFF; updateNZ(regY); };
var opDEA = function(amFn) { regA = (regA-1) & 0xFF; updateNZ(regA); };
var opDEX = function(amFn) { regX = (regX-1) & 0xFF; updateNZ(regX); };
var opDEY = function(amFn) { regY = (regY-1) & 0xFF; updateNZ(regY); };
var opINC = function(amFn) {
var addr = amFn();
var data = memCtrl.getData(addr); // retrieve data from memory
data = memCtrl.getData(addr); // 2nd mem read (new for 65C02)
data = (data + 1) & 0xFF;
memCtrl.setData(addr, data);
updateNZ(data);
};
var opDEC = function(amFn) {
var addr = amFn();
var data = memCtrl.getData(addr); // retrieve data from memory
data = memCtrl.getData(addr); // 2nd mem read (new for 65C02)
data = (data - 1) & 0xFF;
memCtrl.setData(addr, data);
updateNZ(data);
};
var opASL = function(amFn) {
var addr = amFn();
var data = memCtrl.getData(addr); // retrieve data from memory
data = memCtrl.getData(addr); // 2nd mem read (new for 65C02)
regSR.C = (data & 0x80) > 0; // Get the high bit and put it in the carry flag
data = (data << 1) & 0xFF; // shift left and mask
memCtrl.setData(addr, data);
updateNZ(data);
};
var opASL_A = function(amFn) {
regSR.C = (regA & 0x80) > 0;
regA = (regA << 1) & 0xFF;
updateNZ(regA);
};
var opLSR = function(amFn) {
var addr = amFn();
var data = memCtrl.getData(addr); // retrieve data from memory
data = memCtrl.getData(addr); // 2nd mem read (new for 65C02)
regSR.C = (data & 0x01) > 0; // get the low bit and put it in the carry flag
data = (data >> 1) & 0xFF; // shift right and mask
memCtrl.setData(addr, data);
updateNZ(data);
};
var opLSR_A = function(amFn) {
regSR.C = (regA & 0x01) > 0;
regA = (regA >> 1) & 0xFF;
updateNZ(regA);
};
var opROL = function(amFn) {
var addr = amFn();
var data = memCtrl.getData(addr); // retrieve data from memory
data = memCtrl.getData(addr); // 2nd mem read (new for 65C02)
data = (data << 1) | regSR.C; // shift left and add the carry bit
regSR.C = (data & 0x100) > 0; // get bit-8 and put it in the carry flag
data &= 0xFF; // mask the data
memCtrl.setData(addr, data);
updateNZ(data);
};
var opROL_A = function(amFn) {
regA = (regA << 1) | regSR.C;
regSR.C = (regA & 0x100) > 0;
regA &= 0xFF;
updateNZ(regA);
};
var opROR = function(amFn) {
var addr = amFn();
var data = memCtrl.getData(addr); // retrieve data from memory
data = memCtrl.getData(addr); // 2nd mem read (new for 65C02)
var newC = (data & 0x01) > 0; // get new Carry flag from bit 1
data = (data | (regSR.C << 8)) >> 1; // add existing Carry flag and shift right
data &= 0xFF; // mask the data
regSR.C = newC; // set the Carry flag
memCtrl.setData(addr, data);
updateNZ(data);
};
var opROR_A = function(amFn) {
var newC = (regA & 0x01) > 0;
regA = (regA | (regSR.C << 8)) >> 1;
regA &= 0xFF;
regSR.C = newC;
updateNZ(regA);
};
var opAND = function(amFn) { regA = (regA & memCtrl.getData(amFn())) & 0xFF; updateNZ(regA); };
var opORA = function(amFn) { regA = (regA | memCtrl.getData(amFn())) & 0xFF; updateNZ(regA); };
var opEOR = function(amFn) { regA = (regA ^ memCtrl.getData(amFn())) & 0xFF; updateNZ(regA); };
var opBIT = function(amFn) {
var data = memCtrl.getData(amFn());
var result = data & regA;
regSR.Z = (result === 0x00);
if (opcode != 0x89) { // new for 65C02: immediate mode does not affect V and N flags
regSR.V = (data & 0x40) > 0;
regSR.N = (data & 0x80) > 0;
}
};
var opCMP = function(amFn) {
var data = memCtrl.getData(amFn());
regSR.C = (regA >= data);
updateNZ((regA - data) & 0xFF);
};
var opCPX = function(amFn) {
var data = memCtrl.getData(amFn());
regSR.C = (regX >= data);
updateNZ((regX - data) & 0xFF);
};
var opCPY = function(amFn) {
var data = memCtrl.getData(amFn());
regSR.C = (regY >= data);
updateNZ((regY - data) & 0xFF);
};
var opTRB = function(amFn) {
var addr = amFn();
var data = memCtrl.getData(addr);
var result = data & (regA ^ 0xFF);
regSR.Z = (regA & data) === 0;
memCtrl.setData(addr, result);
};
var opTSB = function(amFn) {
var addr = amFn();
var data = memCtrl.getData(addr);
var result = data | regA;
regSR.Z = (regA & data) === 0;
memCtrl.setData(addr, result);
};
var opRMB = function(amFn) {
var addr = amFn();
var bitmask = 1 << (opcode >> 4);
var result = memCtrl.getData(addr) & (bitmask ^ 0xFF);
memCtrl.setData(addr, result);
};
var opSMB = function(amFn) {
var addr = amFn();
var bitmask = 1 << ((opcode >> 4) - 8);
var result = memCtrl.getData(addr) | bitmask;
memCtrl.setData(addr, result);
};
var opADC = function(amFn) {
var data = memCtrl.getData(amFn());
var result;
if (!regSR.D) {
result = regA + data + regSR.C;
} else {
cycle++; // new for 65C02 to make flags in D mode correct
result = (regA & 0x0F) + (data & 0x0F) + regSR.C;
if (result >= 0x0A) { result = ((result + 0x06) & 0x0F) + 0x10; }
result = (regA & 0xF0) + (data & 0xF0) + result;
if (result >= 0xA0) { result += 0x60; }
}
regSR.C = (result & 0x100) > 0;
result &= 0xFF;
regSR.V = ((regA^result)&(data^result)&0x80) > 0;
regA = result;
updateNZ(regA);
};
var opSBC = function(amFn) {
var data = memCtrl.getData(amFn());
var result;
if (!regSR.D) {
result = regA - data - (1 - regSR.C);
} else {
cycle++; // new for 65C02 to make flags in D mode correct
result = (regA & 0x0F) - (data & 0x0F) - (1 - regSR.C);
if (result < 0) {result = ((result - 0x06) & 0x0F) - 0x10; }
result = (regA & 0xF0) - (data & 0xF0) + result;
if (result < 0) {result -= 0x60; }
}
regSR.C = (result >= 0);
result &= 0xFF;
regSR.V = ((regA^result)&((255-data)^result)&0x80) > 0;
regA = result;
updateNZ(regA);
};
var opJMP = function(amFn) { regPC = amFn(); PCinc = 0; };
var opJSR = function(amFn) { pushStackAddr((regPC+2) & 0xFFFF); regPC = amFn(); PCinc = 0;};
var opRTS = function(amFn) { regPC = pullStackAddr(); };
var opRTI = function(amFn) { this.regSR.set(pullStack()); regSR.B = true; regPC = pullStackAddr(); PCinc = 0;};
var opBRA = function(amFn) { regPC = amFn(); };
var opBEQ = function(amFn) { checkBranch(amFn(), regSR.Z); };
var opBNE = function(amFn) { checkBranch(amFn(), !regSR.Z); };
var opBCC = function(amFn) { checkBranch(amFn(), !regSR.C); };
var opBCS = function(amFn) { checkBranch(amFn(), regSR.C); };
var opBVC = function(amFn) { checkBranch(amFn(), !regSR.V); };
var opBVS = function(amFn) { checkBranch(amFn(), regSR.V); };
var opBMI = function(amFn) { checkBranch(amFn(), regSR.N); };
var opBPL = function(amFn) { checkBranch(amFn(), !regSR.N); };
var opBBR = function(amFn) {
var bitmask = 1 << (opcode >> 4);
if ((memCtrl.getData(amFn()) & bitmask) === 0) {
var offset = memCtrl.getData((regPC+2) & 0xFFFF);
if (offset > 127) {
regPC = (regPC + (offset - 256)) & 0xFFFF;
} else {
regPC = (regPC + offset) & 0xFFFF;
}
}
};
var opBBS = function(amFn) {
var bitmask = 1 << ((opcode >> 4) - 8);
if ((memCtrl.getData(amFn()) & bitmask) > 0) {
var offset = memCtrl.getData((regPC+2) & 0xFFFF);
if (offset > 127) {
regPC = (regPC + (offset - 256)) & 0xFFFF;
} else {
regPC = (regPC + offset) & 0xFFFF;
}
}
};
var opCLC = function(amFn) { regSR.C = false; };
var opCLD = function(amFn) { regSR.D = false; };
var opCLI = function(amFn) { regSR.I = false; };
var opCLV = function(amFn) { regSR.V = false; };
var opSEC = function(amFn) { regSR.C = true; };
var opSED = function(amFn) { regSR.D = true; };
var opSEI = function(amFn) { regSR.I = true; };
var opTAX = function(amFn) { regX = regA; updateNZ(regX); };
var opTAY = function(amFn) { regY = regA; updateNZ(regY); };
var opTXA = function(amFn) { regA = regX; updateNZ(regA); };
var opTYA = function(amFn) { regA = regY; updateNZ(regA); };
var opNOP = function(amFn) {
// Different NOP instructions have different byte sizes
// PCinc = 1 by default. This switch statements targets NOPs
// with byte sizes greater than 1
switch (opcode & 0x0F) {
case 0x02:
case 0x04:
PCinc = 2;
break;
case 0x0C:
PCinc = 3;
break;
default:
PCinc = 1;
}
};
var opBRK = function(amFn) {
pushStackAddr(regPC+2); // push PC plus 2 (making BRK a 2-byte instruction)
regSR.B = true;
pushStack(regSR.get()); // push SR with B flag set
regSR.I = true; // set I flag
regSR.D = false; // clear D flag before jumping (new for 65C02)
regPC = memCtrl.getAddr(VECTOR_IRQ);
PCinc = 0;
};
var opWAI = function(amFn) {
regSR.B = true;
waiting = true;
};
var opSTP = function(amFn) {
stopped = true;
waiting = true;
};
// opcode <-> address mode lookup table
this.optable = new Array(256);
this.optable[0x00] = function() {opBRK(amImplicit);};
this.optable[0x01] = function() {opORA(amZPIndirectX);};
this.optable[0x02] = function() {opNOP(amImplicit);};
this.optable[0x03] = function() {opNOP(amImplicit);};
this.optable[0x04] = function() {opTSB(amZeroPage);};
this.optable[0x05] = function() {opORA(amZeroPage);};
this.optable[0x06] = function() {opASL(amZeroPage);};
this.optable[0x07] = function() {opRMB(amZeroPage);};
this.optable[0x08] = function() {opPHP(amImplicit);};
this.optable[0x09] = function() {opORA(amImmediate);};
this.optable[0x0A] = function() {opASL_A(amAccumulator);};
this.optable[0x0B] = function() {opNOP(amImplicit);};
this.optable[0x0C] = function() {opTSB(amAbsolute);};
this.optable[0x0D] = function() {opORA(amAbsolute);};
this.optable[0x0E] = function() {opASL(amAbsolute);};
this.optable[0x0F] = function() {opBBR(amZPRelative);};
this.optable[0x10] = function() {opBPL(amRelative);};
this.optable[0x11] = function() {opORA(amZPIndirectY);};
this.optable[0x12] = function() {opORA(amZPIndirect);};
this.optable[0x13] = function() {opNOP(amImplicit);};
this.optable[0x14] = function() {opTRB(amZeroPage);};
this.optable[0x15] = function() {opORA(amZeroPageX);};
this.optable[0x16] = function() {opASL(amZeroPageX);};
this.optable[0x17] = function() {opRMB(amZeroPage);};
this.optable[0x18] = function() {opCLC(amImplicit);};
this.optable[0x19] = function() {opORA(amAbsoluteY);};
this.optable[0x1A] = function() {opINA(amImplicit);};
this.optable[0x1B] = function() {opNOP(amImplicit);};
this.optable[0x1C] = function() {opTRB(amAbsolute);};
this.optable[0x1D] = function() {opORA(amAbsoluteX);};
this.optable[0x1E] = function() {opASL(amAbsoluteX);};
this.optable[0x1F] = function() {opBBR(amZPRelative);};
this.optable[0x20] = function() {opJSR(amAbsolute);};
this.optable[0x21] = function() {opAND(amZPIndirectX);};
this.optable[0x22] = function() {opNOP(amImplicit);};
this.optable[0x23] = function() {opNOP(amImplicit);};
this.optable[0x24] = function() {opBIT(amZeroPage);};
this.optable[0x25] = function() {opAND(amZeroPage);};
this.optable[0x26] = function() {opROL(amZeroPage);};
this.optable[0x27] = function() {opRMB(amZeroPage);};
this.optable[0x28] = function() {opPLP(amImplicit);};
this.optable[0x29] = function() {opAND(amImmediate);};
this.optable[0x2A] = function() {opROL_A(amAccumulator);};
this.optable[0x2B] = function() {opNOP(amImplicit);};
this.optable[0x2C] = function() {opBIT(amAbsolute);};
this.optable[0x2D] = function() {opAND(amAbsolute);};
this.optable[0x2E] = function() {opROL(amAbsolute);};
this.optable[0x2F] = function() {opBBR(amZPRelative);};
this.optable[0x30] = function() {opBMI(amRelative);};
this.optable[0x31] = function() {opAND(amZPIndirectY);};
this.optable[0x32] = function() {opAND(amZPIndirect);};
this.optable[0x33] = function() {opNOP(amImplicit);};
this.optable[0x34] = function() {opBIT(amZeroPageX);};
this.optable[0x35] = function() {opAND(amZeroPageX);};
this.optable[0x36] = function() {opROL(amZeroPageX);};
this.optable[0x37] = function() {opRMB(amZeroPage);};
this.optable[0x38] = function() {opSEC(amImplicit);};
this.optable[0x39] = function() {opAND(amAbsoluteY);};
this.optable[0x3A] = function() {opDEA(amImplicit);};
this.optable[0x3B] = function() {opNOP(amImplicit);};
this.optable[0x3C] = function() {opBIT(amAbsoluteX);};
this.optable[0x3D] = function() {opAND(amAbsoluteX);};
this.optable[0x3E] = function() {opROL(amAbsoluteX);};
this.optable[0x3F] = function() {opBBR(amZPRelative);};
this.optable[0x40] = function() {opRTI(amImplicit);};
this.optable[0x41] = function() {opEOR(amZPIndirectX);};
this.optable[0x42] = function() {opNOP(amImplicit);};
this.optable[0x43] = function() {opNOP(amImplicit);};
this.optable[0x44] = function() {opNOP(amImplicit);};
this.optable[0x45] = function() {opEOR(amZeroPage);};
this.optable[0x46] = function() {opLSR(amZeroPage);};
this.optable[0x47] = function() {opRMB(amZeroPage);};
this.optable[0x48] = function() {opPHA(amImplicit);};
this.optable[0x49] = function() {opEOR(amImmediate);};
this.optable[0x4A] = function() {opLSR_A(amAccumulator);};
this.optable[0x4B] = function() {opNOP(amImplicit);};
this.optable[0x4C] = function() {opJMP(amAbsolute);};
this.optable[0x4D] = function() {opEOR(amAbsolute);};
this.optable[0x4E] = function() {opLSR(amAbsolute);};
this.optable[0x4F] = function() {opBBR(amZPRelative);};
this.optable[0x50] = function() {opBVC(amRelative);};
this.optable[0x51] = function() {opEOR(amZPIndirectY);};
this.optable[0x52] = function() {opEOR(amZPIndirect);};
this.optable[0x53] = function() {opNOP(amImplicit);};
this.optable[0x54] = function() {opNOP(amImplicit);};
this.optable[0x55] = function() {opEOR(amZeroPageX);};
this.optable[0x56] = function() {opLSR(amZeroPageX);};
this.optable[0x57] = function() {opRMB(amZeroPage);};
this.optable[0x58] = function() {opCLI(amImplicit);};
this.optable[0x59] = function() {opEOR(amAbsoluteY);};
this.optable[0x5A] = function() {opPHY(amImplicit);};
this.optable[0x5B] = function() {opNOP(amImplicit);};
this.optable[0x5C] = function() {opNOP(amImplicit);};
this.optable[0x5D] = function() {opEOR(amAbsoluteX);};
this.optable[0x5E] = function() {opLSR(amAbsoluteX);};
this.optable[0x5F] = function() {opBBR(amZPRelative);};
this.optable[0x60] = function() {opRTS(amImplicit);};
this.optable[0x61] = function() {opADC(amZPIndirectX);};
this.optable[0x62] = function() {opNOP(amImplicit);};
this.optable[0x63] = function() {opNOP(amImplicit);};
this.optable[0x64] = function() {opSTZ(amZeroPage);};
this.optable[0x65] = function() {opADC(amZeroPage);};
this.optable[0x66] = function() {opROR(amZeroPage);};
this.optable[0x67] = function() {opRMB(amZeroPage);};
this.optable[0x68] = function() {opPLA(amImplicit);};
this.optable[0x69] = function() {opADC(amImmediate);};
this.optable[0x6A] = function() {opROR_A(amAccumulator);};
this.optable[0x6B] = function() {opNOP(amImplicit);};
this.optable[0x6C] = function() {opJMP(amIndirect);};
this.optable[0x6D] = function() {opADC(amAbsolute);};
this.optable[0x6E] = function() {opROR(amAbsolute);};
this.optable[0x6F] = function() {opBBR(amZPRelative);};
this.optable[0x70] = function() {opBVS(amRelative);};
this.optable[0x71] = function() {opADC(amZPIndirectY);};
this.optable[0x72] = function() {opADC(amZPIndirect);};
this.optable[0x73] = function() {opNOP(amImplicit);};
this.optable[0x74] = function() {opSTZ(amZeroPageX);};
this.optable[0x75] = function() {opADC(amZeroPageX);};
this.optable[0x76] = function() {opROR(amZeroPageX);};
this.optable[0x77] = function() {opRMB(amZeroPage);};
this.optable[0x78] = function() {opSEI(amImplicit);};
this.optable[0x79] = function() {opADC(amAbsoluteY);};
this.optable[0x7A] = function() {opPLY(amImplicit);};
this.optable[0x7B] = function() {opNOP(amImplicit);};
this.optable[0x7C] = function() {opJMP(amAbsIndIndx);};
this.optable[0x7D] = function() {opADC(amAbsoluteX);};
this.optable[0x7E] = function() {opROR(amAbsoluteX);};
this.optable[0x7F] = function() {opBBR(amZPRelative);};
this.optable[0x80] = function() {opBRA(amRelative);};
this.optable[0x81] = function() {opSTA(amZPIndirectX);};
this.optable[0x82] = function() {opNOP(amImplicit);};
this.optable[0x83] = function() {opNOP(amImplicit);};
this.optable[0x84] = function() {opSTY(amZeroPage);};
this.optable[0x85] = function() {opSTA(amZeroPage);};
this.optable[0x86] = function() {opSTX(amZeroPage);};
this.optable[0x87] = function() {opSMB(amZeroPage);};
this.optable[0x88] = function() {opDEY(amImplicit);};
this.optable[0x89] = function() {opBIT(amImmediate);};
this.optable[0x8A] = function() {opTXA(amImplicit);};
this.optable[0x8B] = function() {opNOP(amImplicit);};
this.optable[0x8C] = function() {opSTY(amAbsolute);};
this.optable[0x8D] = function() {opSTA(amAbsolute);};
this.optable[0x8E] = function() {opSTX(amAbsolute);};
this.optable[0x8F] = function() {opBBS(amZPRelative);};
this.optable[0x90] = function() {opBCC(amRelative);};
this.optable[0x91] = function() {opSTA(amZPIndirectY);};
this.optable[0x92] = function() {opSTA(amZPIndirect);};
this.optable[0x93] = function() {opNOP(amImplicit);};
this.optable[0x94] = function() {opSTY(amZeroPageX);};
this.optable[0x95] = function() {opSTA(amZeroPageX);};
this.optable[0x96] = function() {opSTX(amZeroPageY);};
this.optable[0x97] = function() {opSMB(amZeroPage);};
this.optable[0x98] = function() {opTYA(amImplicit);};
this.optable[0x99] = function() {opSTA(amAbsoluteY);};
this.optable[0x9A] = function() {opTXS(amImplicit);};
this.optable[0x9B] = function() {opNOP(amImplicit);};
this.optable[0x9C] = function() {opSTZ(amAbsolute);};
this.optable[0x9D] = function() {opSTA(amAbsoluteX);};
this.optable[0x9E] = function() {opSTZ(amAbsoluteX);};
this.optable[0x9F] = function() {opBBS(amZPRelative);};
this.optable[0xA0] = function() {opLDY(amImmediate);};
this.optable[0xA1] = function() {opLDA(amZPIndirectX);};
this.optable[0xA2] = function() {opLDX(amImmediate);};
this.optable[0xA3] = function() {opNOP(amImplicit);};
this.optable[0xA4] = function() {opLDY(amZeroPage);};
this.optable[0xA5] = function() {opLDA(amZeroPage);};
this.optable[0xA6] = function() {opLDX(amZeroPage);};
this.optable[0xA7] = function() {opSMB(amZeroPage);};
this.optable[0xA8] = function() {opTAY(amImplicit);};
this.optable[0xA9] = function() {opLDA(amImmediate);};
this.optable[0xAA] = function() {opTAX(amImplicit);};
this.optable[0xAB] = function() {opNOP(amImplicit);};
this.optable[0xAC] = function() {opLDY(amAbsolute);};
this.optable[0xAD] = function() {opLDA(amAbsolute);};
this.optable[0xAE] = function() {opLDX(amAbsolute);};
this.optable[0xAF] = function() {opBBS(amZPRelative);};
this.optable[0xB0] = function() {opBCS(amRelative);};
this.optable[0xB1] = function() {opLDA(amZPIndirectY);};
this.optable[0xB2] = function() {opLDA(amZPIndirect);};
this.optable[0xB3] = function() {opNOP(amImplicit);};
this.optable[0xB4] = function() {opLDY(amZeroPageX);};
this.optable[0xB5] = function() {opLDA(amZeroPageX);};
this.optable[0xB6] = function() {opLDX(amZeroPageY);};
this.optable[0xB7] = function() {opSMB(amZeroPage);};
this.optable[0xB8] = function() {opCLV(amImplicit);};
this.optable[0xB9] = function() {opLDA(amAbsoluteY);};
this.optable[0xBA] = function() {opTSX(amImplicit);};
this.optable[0xBB] = function() {opNOP(amImplicit);};
this.optable[0xBC] = function() {opLDY(amAbsoluteX);};
this.optable[0xBD] = function() {opLDA(amAbsoluteX);};
this.optable[0xBE] = function() {opLDX(amAbsoluteY);};
this.optable[0xBF] = function() {opBBS(amZPRelative);};
this.optable[0xC0] = function() {opCPY(amImmediate);};
this.optable[0xC1] = function() {opCMP(amZPIndirectX);};
this.optable[0xC2] = function() {opNOP(amImplicit);};
this.optable[0xC3] = function() {opNOP(amImplicit);};
this.optable[0xC4] = function() {opCPY(amZeroPage);};
this.optable[0xC5] = function() {opCMP(amZeroPage);};
this.optable[0xC6] = function() {opDEC(amZeroPage);};
this.optable[0xC7] = function() {opSMB(amZeroPage);};
this.optable[0xC8] = function() {opINY(amImplicit);};
this.optable[0xC9] = function() {opCMP(amImmediate);};
this.optable[0xCA] = function() {opDEX(amImplicit);};
this.optable[0xCB] = function() {opWAI(amImplicit);};
this.optable[0xCC] = function() {opCPY(amAbsolute);};
this.optable[0xCD] = function() {opCMP(amAbsolute);};
this.optable[0xCE] = function() {opDEC(amAbsolute);};
this.optable[0xCF] = function() {opBBS(amZPRelative);};
this.optable[0xD0] = function() {opBNE(amRelative);};
this.optable[0xD1] = function() {opCMP(amZPIndirectY);};
this.optable[0xD2] = function() {opCMP(amZPIndirect);};
this.optable[0xD3] = function() {opNOP(amImplicit);};
this.optable[0xD4] = function() {opNOP(amImplicit);};
this.optable[0xD5] = function() {opCMP(amZeroPageX);};
this.optable[0xD6] = function() {opDEC(amZeroPageX);};
this.optable[0xD7] = function() {opSMB(amZeroPage);};
this.optable[0xD8] = function() {opCLD(amImplicit);};
this.optable[0xD9] = function() {opCMP(amAbsoluteY);};
this.optable[0xDA] = function() {opPHX(amImplicit);};
this.optable[0xDB] = function() {opSTP(amImplicit);};
this.optable[0xDC] = function() {opNOP(amImplicit);};
this.optable[0xDD] = function() {opCMP(amAbsoluteX);};
this.optable[0xDE] = function() {opDEC(amAbsoluteX);};
this.optable[0xDF] = function() {opBBS(amZPRelative);};
this.optable[0xE0] = function() {opCPX(amImmediate);};
this.optable[0xE1] = function() {opSBC(amZPIndirectX);};
this.optable[0xE2] = function() {opNOP(amImplicit);};
this.optable[0xE3] = function() {opNOP(amImplicit);};
this.optable[0xE4] = function() {opCPX(amZeroPage);};
this.optable[0xE5] = function() {opSBC(amZeroPage);};
this.optable[0xE6] = function() {opINC(amZeroPage);};
this.optable[0xE7] = function() {opSMB(amZeroPage);};
this.optable[0xE8] = function() {opINX(amImplicit);};
this.optable[0xE9] = function() {opSBC(amImmediate);};
this.optable[0xEA] = function() {opNOP(amImplicit);};
this.optable[0xEB] = function() {opNOP(amImplicit);};
this.optable[0xEC] = function() {opCPX(amAbsolute);};
this.optable[0xED] = function() {opSBC(amAbsolute);};
this.optable[0xEE] = function() {opINC(amAbsolute);};
this.optable[0xEF] = function() {opBBS(amZPRelative);};
this.optable[0xF0] = function() {opBEQ(amRelative);};
this.optable[0xF1] = function() {opSBC(amZPIndirectY);};
this.optable[0xF2] = function() {opSBC(amZPIndirect);};
this.optable[0xF3] = function() {opNOP(amImplicit);};
this.optable[0xF4] = function() {opNOP(amImplicit);};
this.optable[0xF5] = function() {opSBC(amZeroPageX);};
this.optable[0xF6] = function() {opINC(amZeroPageX);};
this.optable[0xF7] = function() {opSMB(amZeroPage);};
this.optable[0xF8] = function() {opSED(amImplicit);};
this.optable[0xF9] = function() {opSBC(amAbsoluteY);};
this.optable[0xFA] = function() {opPLX(amImplicit);};
this.optable[0xFB] = function() {opNOP(amImplicit);};
this.optable[0xFC] = function() {opNOP(amImplicit);};
this.optable[0xFD] = function() {opSBC(amAbsoluteX);};
this.optable[0xFE] = function() {opINC(amAbsoluteX);};
this.optable[0xFF] = function() {opBBS(amZPRelative);};
// CPU Execution Functions
// Run the CPU for a given number of cycles
var run = function(num_cycles) {
var final_cycle = cycle + num_cycles;
// Check for overflow
if (final_cycle < cycle) {
cycle = 0;
final_cycle = num_cycles;
}
while (cycle <= final_cycle && !stopped) {
// handle interrupts
if (this.irq_pin) { this.irq(); if (cycle > final_cycle) return; }
if (this.nmi_pin) { this.nmi(); if (cycle > final_cycle) return; }
if (waiting) return;
opcode = memCtrl.getData(regPC);
PCinc = 1;
cycle += opcycles[opcode];
// Get the opcode function and addressing mode function from the lookup table
optable[opcode]();
regPC = (regPC + PCinc) & 0xFFFF;
}
};
// Reset the CPU
var reset = function() {
regSR.D = false;
regSR.I = true;
regSR.B = true;
stopped = false;
waiting = false;
regPC = memCtrl.getAddr(VECTOR_RST);
cycle += 7;
};
// Interrupt request (via the IRQ pin)
this.irq = function() {
// Only do an IRQ interrupt if I flag is clear and the processor isn't stopped
// Also, NMI interrupts have priority over IRQ
if (! stopped) {
waiting = false; // Allow execution to continue past WAI, even if the IRQ isn't taken
if (!regSR.I && !this.nmi_pin) {
pushStackAddr(regPC); // push PC
regSR.B = false;
pushStack(regSR.get()); // push SR with B flag clear
regSR.I = true; // set interrupt disable flag
regSR.D = false; // clear D flag before jumping (new for 65C02)
regPC = memCtrl.getAddr(VECTOR_IRQ);
PCinc = 0;
cycle += 7;
}
}
};
// Non-maskable interrupt request (via the NMI pin)
var nmi = function() {
// Alway do an IRQ interrupt unless the processor is stopeed
if (!stopped) {
this.nmi_pin = false; // NMI is edge sensitive interrupt
waiting = false;
pushStackAddr(regPC); // push PC
regSR.B = false;
pushStack(regSR.get()); // push SR with B flag clear
regSR.I = true; // set interrupt disable flag
regSR.D = false; // clear D flag before jumping (new for 65C02)
regPC = memCtrl.getAddr(VECTOR_NMI);
PCinc = 0;
cycle += 7;
}
};
return {
irq_pin: this.irq_pin,
nmi_pin: this.nmi_pin,
regA: function() {return regA;},
regX: function() {return regX;},
regY: function() {return regY;},
regSP: function() {return regSP;},
regPC: function() {return regPC;},
regSR: function() {return regSR;},
setA: function(value) {regA = value & 0xFF; },
setX: function(value) {regX = value & 0xFF; },
setY: function(value) {regY = value & 0xFF; },
setSP: function(value) {regSP = value & 0xFF; },
setPC: function(value) {regPC = value & 0xFFFF; },
setSR: function(value) {regSR.set(value); },
cycle: function() {return cycle;},
run: run,
reset: reset,
irq: irq,
nmi: nmi
};
}
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