public override void ExecuteCycle(ICpuState cpuState, IRandomAccessMemory mainMemory)
{
switch (_remainingCycles)
{
case 6:
//read jump address lsb
_jumpAddress = mainMemory.ReadByte(cpuState.ProgramCounter++);
break;
case 5:
//read jump address msb
_jumpAddress |= (ushort)(mainMemory.ReadByte(cpuState.ProgramCounter++) << 8);
break;
case 3:
//write msb of program counter to stack
mainMemory.WriteByte(--cpuState.StackPointer, (byte)(cpuState.ProgramCounter >> 8));
break;
case 2:
//write lsb of program counter to stack
mainMemory.WriteByte(--cpuState.StackPointer, (byte)(cpuState.ProgramCounter & 0x00FF));
break;
case 1:
//do the jump
cpuState.ProgramCounter = _jumpAddress;
break;
}
base.ExecuteCycle(cpuState, mainMemory);
}
public override void ExecuteCycle(ICpuState cpuState, IRandomAccessMemory mainMemory)
{
switch (_remainingCycles)
{
case 4:
//read jump address lsb
_jumpAddress = mainMemory.ReadByte(cpuState.StackPointer++);
break;
case 3:
//read jump address msb
_jumpAddress |= (ushort)(mainMemory.ReadByte(cpuState.StackPointer++) << 8);
break;
case 2:
cpuState.ImeScheduled = true;
break;
case 1:
//do the jump
cpuState.ProgramCounter = _jumpAddress;
break;
}
base.ExecuteCycle(cpuState, mainMemory);
}
public override void ExecuteCycle(ICpuState cpuState, IRandomAccessMemory mainMemory)
{
switch (_remainingCycles)
{
case 5:
_writeAddress = mainMemory.ReadByte(cpuState.ProgramCounter++);
break;
case 4:
_writeAddress |= (ushort)(mainMemory.ReadByte(cpuState.ProgramCounter++) << 8);
break;
case 3:
//write lsb of stack pointer
mainMemory.WriteByte(_writeAddress, (byte)cpuState.StackPointer);
break;
case 2:
//write msb of stack pointer
mainMemory.WriteByte((ushort)(_writeAddress + 1), (byte)(cpuState.StackPointer >> 8));
break;
case 1:
break;
}
base.ExecuteCycle(cpuState, mainMemory);
}
public override void ExecuteCycle(ICpuState cpuState, IRandomAccessMemory mainMemory)
{
switch (_remainingCycles)
{
case 5:
if (!IsConditionMet(cpuState))
{
_remainingCycles = 2;
}
break;
case 4:
//read jump address lsb
_jumpAddress = mainMemory.ReadByte(cpuState.StackPointer++);
break;
case 3:
//read jump address msb
_jumpAddress |= (ushort)(mainMemory.ReadByte(cpuState.StackPointer++) << 8);
break;
case 2:
//do the jump
cpuState.ProgramCounter = _jumpAddress;
break;
}
base.ExecuteCycle(cpuState, mainMemory);
}
internal void RequestVBlankInterrupt()
{
var currentIf = _mainMemory.ReadByte(MiscRegisters.InterruptFlags);
_mainMemory.WriteByte(MiscRegisters.InterruptFlags, (byte)(currentIf | 0x01));
NotifyNextFrameReady();
SwapBuffers();
}
public override void ExecuteCycle(ICpuState cpuState, IRandomAccessMemory mainMemory)
{
switch (_remainingCycles)
{
case 3:
_addressLsb = mainMemory.ReadByte(cpuState.ProgramCounter++);
break;
case 2:
cpuState.Registers.A = mainMemory.ReadByte((ushort)((0xFF << 8) | _addressLsb));
break;
}
base.ExecuteCycle(cpuState, mainMemory);
}
public override void ExecuteCycle(ICpuState cpuState, IRandomAccessMemory mainMemory)
{
switch (_remainingCycles)
{
case 3:
//read jump address lsb
_relativeAddress = (sbyte)mainMemory.ReadByte(cpuState.ProgramCounter++);
break;
case 2:
//set last cycle if condition is not met
if (!IsConditionMet(cpuState))
{
_remainingCycles = 1;
}
break;
case 1:
//do the jump
cpuState.ProgramCounter = (ushort)(cpuState.ProgramCounter + _relativeAddress);
break;
}
base.ExecuteCycle(cpuState, mainMemory);
}
public override void ExecuteCycle(ICpuState cpuState, IRandomAccessMemory mainMemory)
{
switch (_remainingCycles)
{
case 2:
_addData = mainMemory.ReadByte(cpuState.ProgramCounter++);
break;
case 1:
var oldValue = cpuState.Registers.A;
int result = cpuState.Registers.A + _addData;
if (cpuState.Registers.CarryFlag)
{
result++;
}
cpuState.Registers.A = (byte)result;
cpuState.Registers.SubtractionFlag = false;
cpuState.Registers.ZeroFlag = cpuState.Registers.A == 0;
cpuState.Registers.HalfCarryFlag = (((oldValue & 0xF) + (_addData & 0xF)
+ (cpuState.Registers.CarryFlag ? 1 : 0)) & 0x10) == 0x10;
cpuState.Registers.CarryFlag = result > 0xFF;
break;
}
base.ExecuteCycle(cpuState, mainMemory);
}
public override void ExecuteCycle(ICpuState cpuState, IRandomAccessMemory mainMemory)
{
var interruptEnable = mainMemory.ReadByte(MiscRegisters.InterruptEnable);
var interruptFlags = mainMemory.ReadByte(MiscRegisters.InterruptFlags);
if (!cpuState.InterruptMasterEnable && (interruptEnable & interruptFlags & 0x1F) != 0)
{
cpuState.HaltBug = true;
}
else
{
cpuState.HaltMode = true;
}
base.ExecuteCycle(cpuState, mainMemory);
}
public override void ExecuteCycle(ICpuState cpuState, IRandomAccessMemory mainMemory)
{
switch (_remainingCycles)
{
case 3:
_currentData = mainMemory.ReadByte(cpuState.Registers.HL);
break;
case 2:
byte lowNibble = (byte)(_currentData & 0x0F);
byte highNibble = (byte)(_currentData & 0xF0);
_writeData = (byte)((lowNibble << 4) | (highNibble >> 4));
mainMemory.WriteByte(cpuState.Registers.HL, _writeData);
cpuState.Registers.ZeroFlag = _writeData == 0;
cpuState.Registers.HalfCarryFlag = false;
cpuState.Registers.SubtractionFlag = false;
cpuState.Registers.CarryFlag = false;
break;
}
base.ExecuteCycle(cpuState, mainMemory);
}
public override void ExecuteCycle(ICpuState cpuState, IRandomAccessMemory mainMemory)
{
switch (_remainingCycles)
{
case 4:
_signedValue = (sbyte)mainMemory.ReadByte(cpuState.ProgramCounter++);
_oldValue = cpuState.StackPointer;
break;
case 3:
cpuState.StackPointer = (ushort)(cpuState.StackPointer + _signedValue);
break;
case 1:
if (_signedValue >= 0)
{
cpuState.Registers.CarryFlag = ((_oldValue & 0xFF) + (_signedValue)) > 0xFF;
cpuState.Registers.HalfCarryFlag = ((_oldValue & 0xF) + (_signedValue & 0xF)) > 0xF;
}
else
{
cpuState.Registers.CarryFlag = (cpuState.StackPointer & 0xFF) <= (_oldValue & 0xFF);
cpuState.Registers.HalfCarryFlag = (cpuState.StackPointer & 0xF) <= (_oldValue & 0xF);
}
cpuState.Registers.ZeroFlag = false;
cpuState.Registers.SubtractionFlag = false;
break;
}
base.ExecuteCycle(cpuState, mainMemory);
}
public override void ExecuteCycle(ICpuState cpuState, IRandomAccessMemory mainMemory)
{
switch (_remainingCycles)
{
case 3:
_currentData = mainMemory.ReadByte(cpuState.Registers.HL);
break;
case 2:
_hiBit = _currentData & 0x80;
_loBit = _currentData & 0x01;
_writeData = (byte)(_currentData >> 1);
_writeData |= (byte)_hiBit;
mainMemory.WriteByte(cpuState.Registers.HL, _writeData);
cpuState.Registers.CarryFlag = _loBit == 0x01;
cpuState.Registers.ZeroFlag = _writeData == 0;
cpuState.Registers.HalfCarryFlag = false;
cpuState.Registers.SubtractionFlag = false;
break;
}
base.ExecuteCycle(cpuState, mainMemory);
}
public override void ExecuteCycle(ICpuState cpuState, IRandomAccessMemory mainMemory)
{
switch (_remainingCycles)
{
case 2:
_subData = mainMemory.ReadByte(cpuState.ProgramCounter++);
break;
case 1:
var oldValue = cpuState.Registers.A;
cpuState.Registers.A -= _subData;
if (cpuState.Registers.CarryFlag)
{
cpuState.Registers.A--;
}
cpuState.Registers.SubtractionFlag = true;
cpuState.Registers.ZeroFlag = cpuState.Registers.A == 0;
cpuState.Registers.HalfCarryFlag = ((_subData & 0x0F)
+ (cpuState.Registers.CarryFlag ? 1 : 0)) > (oldValue & 0xF);
cpuState.Registers.CarryFlag = (_subData + (cpuState.Registers.CarryFlag ? 1 : 0)) > oldValue;
break;
}
base.ExecuteCycle(cpuState, mainMemory);
}
public override void ExecuteCycle(ICpuState cpuState, IRandomAccessMemory mainMemory)
{
switch (_remainingCycles)
{
case 4:
_address = mainMemory.ReadByte(cpuState.ProgramCounter++);
break;
case 3:
_address |= (ushort)(mainMemory.ReadByte(cpuState.ProgramCounter++) << 8);
break;
case 2:
mainMemory.WriteByte(_address, cpuState.Registers.A);
break;
}
base.ExecuteCycle(cpuState, mainMemory);
}
public override void ExecuteCycle(ICpuState cpuState, IRandomAccessMemory mainMemory)
{
switch (_remainingCycles)
{
case 3:
_registerBits = (byte)((_opcode >> 4) & 0x03);
var lsbData = mainMemory.ReadByte(cpuState.StackPointer++);
WriteToRegister(cpuState, lsbData, true);
break;
case 2:
var msbData = mainMemory.ReadByte(cpuState.StackPointer++);
WriteToRegister(cpuState, msbData, false);
break;
}
base.ExecuteCycle(cpuState, mainMemory);
}
public override void ExecuteCycle(ICpuState cpuState, IRandomAccessMemory mainMemory)
{
switch (_remainingCycles)
{
case 2:
cpuState.Registers.A = mainMemory.ReadByte((ushort)((0xFF << 8) | cpuState.Registers.C));
break;
}
base.ExecuteCycle(cpuState, mainMemory);
}
public override void ExecuteCycle(ICpuState cpuState, IRandomAccessMemory mainMemory)
{
switch (_remainingCycles)
{
case 3:
_registerBits = (byte)((_opcode >> 4) & 0x03);
_loadData = mainMemory.ReadByte(cpuState.ProgramCounter++);
break;
case 2:
_loadData |= (ushort)(mainMemory.ReadByte(cpuState.ProgramCounter++) << 8);
break;
case 1:
switch (_registerBits)
{
case 0b00:
cpuState.Registers.BC = _loadData;
break;
case 0b01:
cpuState.Registers.DE = _loadData;
break;
case 0b10:
cpuState.Registers.HL = _loadData;
break;
case 0b11:
cpuState.StackPointer = _loadData;
break;
}
break;
}
base.ExecuteCycle(cpuState, mainMemory);
}
public override void ExecuteCycle(ICpuState cpuState, IRandomAccessMemory mainMemory)
{
switch (_remainingCycles)
{
case 3:
_loadData = mainMemory.ReadByte(cpuState.ProgramCounter++);
break;
case 2:
mainMemory.WriteByte(cpuState.Registers.HL, _loadData);
break;
}
base.ExecuteCycle(cpuState, mainMemory);
}
public override void ExecuteCycle(ICpuState cpuState, IRandomAccessMemory mainMemory)
{
switch (_remainingCycles)
{
case 2:
_loadData = mainMemory.ReadByte(cpuState.Registers.BC);
break;
case 1:
cpuState.Registers.A = _loadData;
break;
}
base.ExecuteCycle(cpuState, mainMemory);
}
public override void ExecuteCycle(ICpuState cpuState, IRandomAccessMemory mainMemory)
{
switch (_remainingCycles)
{
case 2:
_registerIndex = (_opcode >> 3) & 0x07;
_loadData = mainMemory.ReadByte(cpuState.Registers.HL);
break;
case 1:
cpuState.Registers[_registerIndex] = _loadData;
break;
}
base.ExecuteCycle(cpuState, mainMemory);
}
public override void ExecuteCycle(ICpuState cpuState, IRandomAccessMemory mainMemory)
{
switch (_remainingCycles)
{
case 3:
//read jump address lsb
_relativeAddress = (sbyte)mainMemory.ReadByte(cpuState.ProgramCounter++);
break;
case 1:
//do the jump
cpuState.ProgramCounter = (ushort)(cpuState.ProgramCounter + _relativeAddress);
break;
}
base.ExecuteCycle(cpuState, mainMemory);
}
public override void ExecuteCycle(ICpuState cpuState, IRandomAccessMemory mainMemory)
{
switch (_remainingCycles)
{
case 3:
_currentData = mainMemory.ReadByte(cpuState.Registers.HL);
var bitIndex = (_opcode & 0x38) >> 3;
_writeData = (byte)(_currentData & ~(0x01 << bitIndex));
break;
case 2:
mainMemory.WriteByte(cpuState.Registers.HL, _writeData);
break;
}
base.ExecuteCycle(cpuState, mainMemory);
}
public override void ExecuteCycle(ICpuState cpuState, IRandomAccessMemory mainMemory)
{
switch (_remainingCycles)
{
case 2:
_currentData = mainMemory.ReadByte(cpuState.Registers.HL);
break;
case 1:
var bitIndex = (_opcode & 0x38) >> 3;
cpuState.Registers.ZeroFlag = ((byte)(_currentData >> bitIndex) & 0x01) == 0;
cpuState.Registers.HalfCarryFlag = true;
cpuState.Registers.SubtractionFlag = false;
break;
}
base.ExecuteCycle(cpuState, mainMemory);
}
public override void ExecuteCycle(ICpuState cpuState, IRandomAccessMemory mainMemory)
{
switch (_remainingCycles)
{
case 2:
_subData = mainMemory.ReadByte(cpuState.ProgramCounter++);
break;
case 1:
cpuState.Registers.SubtractionFlag = true;
cpuState.Registers.ZeroFlag = cpuState.Registers.A - _subData == 0;
cpuState.Registers.HalfCarryFlag = ((cpuState.Registers.A & 0xF) - (_subData & 0xF)) < 0;
cpuState.Registers.CarryFlag = _subData > cpuState.Registers.A;
break;
}
base.ExecuteCycle(cpuState, mainMemory);
}
public override void ExecuteCycle(ICpuState cpuState, IRandomAccessMemory mainMemory)
{
switch (_remainingCycles)
{
case 2:
_data = mainMemory.ReadByte(cpuState.Registers.HL);
break;
case 1:
cpuState.Registers.A |= _data;
break;
}
cpuState.Registers.SubtractionFlag = false;
cpuState.Registers.ZeroFlag = cpuState.Registers.A == 0;
cpuState.Registers.HalfCarryFlag = false;
cpuState.Registers.CarryFlag = false;
base.ExecuteCycle(cpuState, mainMemory);
}
public override void ExecuteCycle(ICpuState cpuState, IRandomAccessMemory mainMemory)
{
switch (_remainingCycles)
{
case 3:
_currentData = mainMemory.ReadByte(cpuState.Registers.HL);
break;
case 2:
_decrementedData = (byte)(_currentData - 1);
mainMemory.WriteByte(cpuState.Registers.HL, _decrementedData);
break;
case 1:
cpuState.Registers.ZeroFlag = _decrementedData == 0;
cpuState.Registers.SubtractionFlag = true;
cpuState.Registers.HalfCarryFlag = (_currentData & 0x0F) == 0;
break;
}
base.ExecuteCycle(cpuState, mainMemory);
}
public override void ExecuteCycle(ICpuState cpuState, IRandomAccessMemory mainMemory)
{
switch (_remainingCycles)
{
case 2:
_addData = mainMemory.ReadByte(cpuState.Registers.HL);
break;
case 1:
var oldValue = cpuState.Registers.A;
cpuState.Registers.A += _addData;
cpuState.Registers.SubtractionFlag = false;
cpuState.Registers.ZeroFlag = cpuState.Registers.A == 0;
cpuState.Registers.HalfCarryFlag = (((oldValue & 0xF) + (_addData & 0xF)) & 0x10) == 0x10;
cpuState.Registers.CarryFlag = cpuState.Registers.A < oldValue;
break;
}
base.ExecuteCycle(cpuState, mainMemory);
}
public override void ExecuteCycle(ICpuState cpuState, IRandomAccessMemory mainMemory)
{
switch (_remainingCycles)
{
case 2:
_subData = mainMemory.ReadByte(cpuState.Registers.HL);
break;
case 1:
var oldValue = cpuState.Registers.A;
cpuState.Registers.A -= _subData;
cpuState.Registers.SubtractionFlag = true;
cpuState.Registers.ZeroFlag = cpuState.Registers.A == 0;
cpuState.Registers.HalfCarryFlag = ((oldValue & 0xF) - (_subData & 0xF)) < 0;
cpuState.Registers.CarryFlag = _subData > oldValue;
break;
}
base.ExecuteCycle(cpuState, mainMemory);
}
public byte MemoryRead(ushort address)
{
return(_mainMemory.ReadByte(address));
}
public override void ExecuteCycle(ICpuState cpuState, IRandomAccessMemory mainMemory)
{
switch (_remainingCycles)
{
case 3:
mainMemory.WriteByte(--cpuState.StackPointer, (byte)(cpuState.ProgramCounter >> 8));
break;
case 2:
mainMemory.WriteByte(--cpuState.StackPointer, (byte)(cpuState.ProgramCounter & 0x00FF));
break;
case 1:
var interruptFlags = mainMemory.ReadByte(MiscRegisters.InterruptFlags);
//vblank interrupt
if ((_readyInterrupts & 0x01) == 0x01)
{
//Console.WriteLine("Loading vblank isr...");
cpuState.ProgramCounter = InterruptAddresses.VblankInterrupt;
mainMemory.WriteByte(MiscRegisters.InterruptFlags, (byte)(interruptFlags & 0xFE));
}
//lcd stat interrupt
else if ((_readyInterrupts & 0x02) == 0x02)
{
//Console.WriteLine("Loading lcd stat isr...");
cpuState.ProgramCounter = InterruptAddresses.LcdInterrupt;
//clear interrupt flag
mainMemory.WriteByte(MiscRegisters.InterruptFlags, (byte)(interruptFlags & 0xFD));
}
//timer interrupt
else if ((_readyInterrupts & 0x04) == 0x04)
{
//Console.WriteLine("Loading timer isr...");
cpuState.ProgramCounter = InterruptAddresses.TimerInterrupt;
//clear interrupt flag
mainMemory.WriteByte(MiscRegisters.InterruptFlags, (byte)(interruptFlags & 0xFB));
}
//serial interrupt
else if ((_readyInterrupts & 0x08) == 0x08)
{
cpuState.ProgramCounter = InterruptAddresses.SerialInterrupt;
//clear interrupt flag
mainMemory.WriteByte(MiscRegisters.InterruptFlags, (byte)(interruptFlags & 0xF7));
}
//joypad interrupt
else if ((_readyInterrupts & 0x10) == 0x10)
{
cpuState.ProgramCounter = InterruptAddresses.JoypadInterrupt;
//clear interrupt flag
mainMemory.WriteByte(MiscRegisters.InterruptFlags, (byte)(interruptFlags & 0x0F));
}
cpuState.InterruptMasterEnable = false;
break;
}
base.ExecuteCycle(cpuState, mainMemory);
}