private void IncrementInstructionRegister(OpCodeData opCodeData)
{
UInt16 instructionRegisterValue = _instructionRegister.GetRegisterValue();
Byte vXValue = _registers.GetRegisterValue(opCodeData.X);
_instructionRegister.SetRegisterValue(value: (UInt16)(instructionRegisterValue + vXValue));
}
public override void Execute(OpCodeData opCodeData)
{
Byte vX = _registers.GetRegisterValue(opCodeData.X);
Byte vY = _registers.GetRegisterValue(opCodeData.Y);
if (vX == vY)
{
UInt16 programCounter = _programCounter.GetRegisterValue();
programCounter += 2;
_programCounter.SetRegisterValue(value: programCounter);
}
}
public void Tick()
{
UInt16 currentMemoryLocation = _programCounter.GetRegisterValue(0x0);
Byte[] opCodeBytes = new Byte[2] {
_memory.GetValueAtLocation(currentMemoryLocation++),
_memory.GetValueAtLocation(currentMemoryLocation++)
};
_programCounter.SetRegisterValue(value: currentMemoryLocation);
UInt16 currentInstruction = (UInt16)((opCodeBytes[0] << 8) + opCodeBytes[1]);
Trace.WriteLine(currentInstruction);
OpCodeData opCodeData = new OpCodeData
{
Address = (UInt16)(currentInstruction & 0x0FFF),
Nibble = (Byte)(currentInstruction & 0x000F),
OpCode = currentInstruction,
Value = (Byte)(currentInstruction & 0x00FF),
X = (Byte)((currentInstruction & 0x0F00) >> 8),
Y = (Byte)((currentInstruction & 0x00F0) >> 4)
};
_opCodesDirector.HandleOpCode(opCodeData);
Trace.WriteLine(_generalPurposeRegisters.DebugString());
_cpuTimer.Start();
}
public override void Execute(OpCodeData opCodeData)
{
UInt16 currentAddress = _programCounter.GetRegisterValue();
_stackPointer.Push(currentAddress);
_programCounter.SetRegisterValue(value: opCodeData.Address);
}
public override void Execute(OpCodeData opCodeData)
{
Byte registerValue = _registers.GetRegisterValue(opCodeData.X);
registerValue += opCodeData.Value;
_registers.SetRegisterValue(opCodeData.X, registerValue);
}
public override void Execute(OpCodeData opCodeData)
{
Byte registerValue = _registers.GetRegisterValue(opCodeData.X);
if (registerValue != opCodeData.Value)
{
UInt16 programCounter = _programCounter.GetRegisterValue();
programCounter += 2;
_programCounter.SetRegisterValue(value: programCounter);
}
}
public override void Execute(OpCodeData opCodeData)
{
Byte sizeOfSprite = opCodeData.Nibble;
Byte startingX = _registers.GetRegisterValue(opCodeData.X);
Byte startingY = _registers.GetRegisterValue(opCodeData.Y);
UInt16 instructionRegisterLocation = _instructionRegister.GetRegisterValue();
Trace.WriteLine($"{startingX},{startingY}");
_registers.SetRegisterValue(0xF, 0x0);
for (Byte spritePosition = 0; spritePosition < sizeOfSprite; spritePosition++)
{
Byte spriteByte = _memory.GetValueAtLocation((UInt16)(instructionRegisterLocation + spritePosition));
BitArray bitArray = new BitArray(new Byte[] { spriteByte });
for (Byte bitArrayIndex = 7; bitArrayIndex > 0; bitArrayIndex--)
{
Byte xPosition = (Byte)((startingX + (7 - bitArrayIndex)) % _screenWidth);
Byte yPosition = (Byte)((startingY + spritePosition) % _screenHeight);
Boolean oldState = _screen.GetStateAtLocation(xPosition, yPosition);
Boolean spriteState = bitArray[bitArrayIndex];
Boolean newState = oldState ^ spriteState;
if (oldState != spriteState)
{
_screen.SetDirtyFlag();
}
_screen.SetStateAtLocation(xPosition, yPosition, newState);
if (oldState == true && newState == false)
{
_registers.SetRegisterValue(0xF, 0x1);
}
}
}
}
public override void Execute(OpCodeData opCodeData)
{
Byte vXValue = _registers.GetRegisterValue(opCodeData.X);
UInt16 programCounterValue = _programCounter.GetRegisterValue();
if (opCodeData.Value == 0x9E)
{
if (_keyManager.IsKeyPressed(vXValue) == true)
{
_programCounter.SetRegisterValue(value: (UInt16)(programCounterValue + 2));
}
}
else if (opCodeData.Value == 0xA1)
{
if (_keyManager.IsKeyPressed(vXValue) == false)
{
_programCounter.SetRegisterValue(value: (UInt16)(programCounterValue + 2));
}
}
}
public override void Execute(OpCodeData opCodeData)
{
Byte v0Value = _registers.GetRegisterValue(0x0);
_programCounter.SetRegisterValue(value: (UInt16)(v0Value + opCodeData.Address));
}
private void AddAndCarry(OpCodeData opCodeData)
{
Byte vXValue = _registers.GetRegisterValue(opCodeData.X);
Byte vYValue = _registers.GetRegisterValue(opCodeData.Y);
UInt16 result = (UInt16)(vXValue + vYValue);
if (result > 0xFF)
{
_registers.SetRegisterValue(0xF, 0x1);
}
_registers.SetRegisterValue(opCodeData.X, (Byte)(vXValue + vYValue));
}