public Chip(Action <PropertyObservationWrapper <short>, PropertyChangedEventArgs> registerActionShort,
Action <PropertyObservationWrapper <byte>, PropertyChangedEventArgs> registerActionByte,
Action <PropertyObservationWrapper <bool>, PropertyChangedEventArgs> flagChangedAction,
List <BaseInstruction> instructions)
{
for (int i = 0; i < instructions.Count; i++)
{
OffsetToIndexMap.Add((short)(instructions[i].ByteOffset + Helper.InitialOffset), i);
IndexToOffsetMap.Add(i, (short)(instructions[i].ByteOffset + Helper.InitialOffset));
}
foreach (var kvp in Flags)
{
kvp.Value.PropertyChanged += flagChangedAction;
}
this.instructions = instructions;
XRegister = new PropertyObservationWrapper <byte>(0, "X-Register");
XRegister.PropertyChanged += registerActionByte;
YRegister = new PropertyObservationWrapper <byte>(0, "Y-Register");
YRegister.PropertyChanged += registerActionByte;
AccumulatorRegister = new PropertyObservationWrapper <byte>(0, "Accumulator Register");
AccumulatorRegister.PropertyChanged += registerActionByte;
StackPointer = new PropertyObservationWrapper <byte>(0, "Stack Pointer");
StackPointer.PropertyChanged += registerActionByte;
ProgramCounter = new PropertyObservationWrapper <short>(Helper.InitialOffset, "Program Counter");
ProgramCounter.PropertyChanged += registerActionShort;
}
public void EmulateSingleInstruction()
{
if (Finished)
{
return;
}
var instruction = instructions[OffsetToIndexMap[ProgramCounter.Value]];
switch (instruction.Type)
{
case InstructionType.ADC:
switch (instruction.Mode)
{
case AddressingModes.Immediate:
{
byte byteValueToAddToAccumulator = instruction.Parameters[0];
byte carryFlag = Flags[FlagType.C].Value ? (byte)1 : (byte)0;
byte result = (byte)(AccumulatorRegister.Value + byteValueToAddToAccumulator + carryFlag);
bool isSeventhBitCarry1 = byteValueToAddToAccumulator >> 7 == 1 && AccumulatorRegister.Value >> 7 == 1;
Flags[FlagType.Z].Value = result == 0;
Flags[FlagType.S].Value = (result >> 7) == 1;
Flags[FlagType.C].Value = isSeventhBitCarry1;
Flags[FlagType.V].Value = ((sbyte)AccumulatorRegister.Value).WillAdditionOverflow((sbyte)byteValueToAddToAccumulator + carryFlag);
AccumulatorRegister.Value = result;
}
break;
case AddressingModes.ZeroPage:
{
var address = instruction.Parameters[0];
byte byteValueToAddToAccumulator = Computer.Ram[address].Value;
byte carryFlag = Flags[FlagType.C].Value ? (byte)1 : (byte)0;
byte result = (byte)(AccumulatorRegister.Value + byteValueToAddToAccumulator + carryFlag);
bool isSeventhBitCarry1 = byteValueToAddToAccumulator >> 7 == 1 && AccumulatorRegister.Value >> 7 == 1;
Flags[FlagType.Z].Value = result == 0;
Flags[FlagType.S].Value = (result >> 7) == 1;
Flags[FlagType.C].Value = isSeventhBitCarry1;
Flags[FlagType.V].Value = ((sbyte)AccumulatorRegister.Value).WillAdditionOverflow((sbyte)byteValueToAddToAccumulator + carryFlag);
AccumulatorRegister.Value = result;
}
break;
case AddressingModes.ZeroPageX:
break;
case AddressingModes.Absolute:
break;
case AddressingModes.AbsoluteX:
break;
case AddressingModes.AbsoluteY:
break;
case AddressingModes.IndirectX:
break;
case AddressingModes.IndirectY:
break;
}
break;
case InstructionType.AND:
break;
case InstructionType.ASL:
break;
case InstructionType.BCC:
break;
case InstructionType.BCS:
break;
case InstructionType.BEQ:
break;
case InstructionType.BIT:
break;
case InstructionType.BMI:
switch (instruction.Mode)
{
case AddressingModes.Relative:
if (Flags[FlagType.S].Value == true)
{
ProgramCounter.Value += (short)((sbyte)instruction.Parameters[0]);
}
break;
}
break;
case InstructionType.BNE:
switch (instruction.Mode)
{
case AddressingModes.Relative:
if (Flags[FlagType.Z].Value == false)
{
ProgramCounter.Value += (short)((sbyte)instruction.Parameters[0]);
}
break;
}
break;
case InstructionType.BPL:
break;
case InstructionType.BRK:
break;
case InstructionType.BVC:
break;
case InstructionType.BVS:
break;
case InstructionType.CLC:
break;
case InstructionType.CLD:
break;
case InstructionType.CLI:
break;
case InstructionType.CLV:
break;
case InstructionType.CMP:
break;
case InstructionType.CPX:
switch (instruction.Mode)
{
case AddressingModes.Immediate:
//A, X, or Y <Memory --->N = 1, Z = 0, C = 0
//A, X, or Y = Memory---> N = 0, Z = 1, C = 1
//A, X, or Y > Memory---> N = 0, Z = 0, C = 1
var compareTo = instruction.Parameters[0];
Flags[FlagType.S].Value = (XRegister.Value < compareTo);
Flags[FlagType.Z].Value = (XRegister.Value == compareTo);
Flags[FlagType.C].Value = (XRegister.Value >= compareTo);
break;
}
break;
case InstructionType.CPY:
break;
case InstructionType.DEC:
break;
case InstructionType.DEX:
switch (instruction.Mode)
{
case AddressingModes.Implied:
Flags[FlagType.S].Value = ((sbyte)XRegister.Value).WillSubtractionUnderflow(1);
Flags[FlagType.Z].Value = XRegister.Value - 1 == 0;
XRegister.Value -= 1;
break;
}
break;
case InstructionType.DEY:
break;
case InstructionType.EOR:
break;
case InstructionType.INC:
break;
//FINISHED
case InstructionType.INX:
switch (instruction.Mode)
{
case AddressingModes.Implied:
var result = XRegister.Value + 1;
Flags[FlagType.V].Value = ((sbyte)XRegister.Value).WillAdditionOverflow(1);
Flags[FlagType.S].Value = (result >> 7) == 1;
XRegister.Value += 1;
break;
}
break;
//FINISHED
case InstructionType.INY:
switch (instruction.Mode)
{
case AddressingModes.Implied:
var result = YRegister.Value + 1;
Flags[FlagType.Z].Value = ((sbyte)YRegister.Value).WillAdditionOverflow(1);
Flags[FlagType.S].Value = (result >> 7) == 1;
YRegister.Value += 1;
break;
}
break;
case InstructionType.JMP:
break;
case InstructionType.JSR:
switch (instruction.Mode)
{
case AddressingModes.JumpLabel:
var lowByte = instruction.Parameters[0];
var highByte = instruction.Parameters[1];
short address = (short)((highByte << 8) + lowByte);
break;
}
break;
case InstructionType.LDA:
switch (instruction.Mode)
{
case AddressingModes.Immediate:
{
var value = instruction.Parameters[0];
AccumulatorRegister.Value = value;
Flags[FlagType.V].Value = ((sbyte)AccumulatorRegister.Value).WillAdditionOverflow(0);
Flags[FlagType.S].Value = (AccumulatorRegister.Value >> 7) == 1;
}
break;
case AddressingModes.ZeroPage:
{
var address = instruction.Parameters[0];
AccumulatorRegister.Value = Computer.Ram[address].Value;
Flags[FlagType.V].Value = ((sbyte)AccumulatorRegister.Value).WillAdditionOverflow(0);
Flags[FlagType.S].Value = (AccumulatorRegister.Value >> 7) == 1;
}
break;
case AddressingModes.ZeroPageX:
break;
case AddressingModes.Absolute:
break;
case AddressingModes.AbsoluteX:
break;
case AddressingModes.AbsoluteY:
break;
case AddressingModes.IndirectX:
break;
case AddressingModes.IndirectY:
break;
}
break;
case InstructionType.LDX:
switch (instruction.Mode)
{
case AddressingModes.Immediate:
{
var value = instruction.Parameters[0];
XRegister.Value = value;
Flags[FlagType.V].Value = ((sbyte)XRegister.Value).WillAdditionOverflow(0);
Flags[FlagType.S].Value = (XRegister.Value >> 7) == 1;
}
break;
}
break;
case InstructionType.LDY:
break;
case InstructionType.LSR:
break;
case InstructionType.NOP:
break;
case InstructionType.ORA:
break;
case InstructionType.PHA:
break;
case InstructionType.PHP:
break;
case InstructionType.PLA:
break;
case InstructionType.PLP:
break;
case InstructionType.ROL:
break;
case InstructionType.ROR:
break;
case InstructionType.RTI:
break;
case InstructionType.RTS:
break;
case InstructionType.SBC:
break;
case InstructionType.SEC:
break;
case InstructionType.SED:
break;
case InstructionType.SEI:
break;
case InstructionType.STA:
switch (instruction.Mode)
{
case AddressingModes.ZeroPage:
{
var address = instruction.Parameters[0];
Computer.Ram[address].Value = AccumulatorRegister.Value;
}
break;
case AddressingModes.ZeroPageX:
break;
case AddressingModes.Absolute:
{
var lowByte = instruction.Parameters[0];
var highByte = instruction.Parameters[1];
short address = (short)((highByte << 8) + lowByte);
if (MMIO.AddressToIndex.ContainsKey(address))
{
var encodedData = AccumulatorRegister.Value;
var red = (encodedData >> 5) * 32;
var green = ((encodedData & 28) >> 2) * 32;
var blue = (encodedData & 3) * 64;
var col = Color.FromArgb(255, red, green, blue);
var index = MMIO.AddressToIndex[address];
var twoDIndex = index.OneToTwoD(MMIO.Bitmap.Width);
MMIO.Bitmap.SetPixel(twoDIndex.X, twoDIndex.Y, col);
}
}
break;
case AddressingModes.AbsoluteX:
{
var lowByte = instruction.Parameters[0];
var highByte = instruction.Parameters[1];
short address = (short)((highByte << 8) + lowByte);
var offset = XRegister.Value;
short final = (short)(address + offset);
if (MMIO.AddressToIndex.ContainsKey(final))
{
var encodedData = AccumulatorRegister.Value;
var red = (encodedData >> 5) * 32;
var green = ((encodedData & 28) >> 2) * 32;
var blue = (encodedData & 3) * 64;
var col = Color.FromArgb(255, red, green, blue);
var index = MMIO.AddressToIndex[final];
var twoDIndex = index.OneToTwoD(MMIO.Bitmap.Width);
MMIO.Bitmap.SetPixel(twoDIndex.X, twoDIndex.Y, col);
}
Computer.Ram[address + offset].Value = AccumulatorRegister.Value;
}
break;
case AddressingModes.AbsoluteY:
break;
case AddressingModes.IndirectX:
break;
case AddressingModes.IndirectY:
break;
}
break;
case InstructionType.STX:
switch (instruction.Mode)
{
case AddressingModes.ZeroPage:
{
var address = instruction.Parameters[0];
Computer.Ram[address].Value = XRegister.Value;
ProgramCounter.Value += 3;
}
break;
case AddressingModes.ZeroPageY:
break;
case AddressingModes.Absolute:
{
var lowByte = instruction.Parameters[0];
var highByte = instruction.Parameters[1];
short address = (short)((highByte << 8) + lowByte);
if (MMIO.AddressToIndex.ContainsKey(address))
{
var encodedData = XRegister.Value;
var red = (encodedData >> 5) * 32;
var green = ((encodedData & 28) >> 2) * 32;
var blue = (encodedData & 3) * 64;
var col = Color.FromArgb(255, red, green, blue);
var index = MMIO.AddressToIndex[address];
var twoDIndex = index.OneToTwoD(MMIO.Bitmap.Width);
MMIO.Bitmap.SetPixel(twoDIndex.X, twoDIndex.Y, col);
}
}
break;
}
break;
case InstructionType.STY:
break;
case InstructionType.TAX:
switch (instruction.Mode)
{
case AddressingModes.Implied:
XRegister.Value = AccumulatorRegister.Value;
break;
}
break;
case InstructionType.TAY:
break;
case InstructionType.TSX:
break;
case InstructionType.TXA:
break;
case InstructionType.TXS:
break;
case InstructionType.TYA:
break;
}
//If there is a brach or jump we need to return early with a different index
var newIndex = OffsetToIndexMap[ProgramCounter.Value] + 1;
if (IndexToOffsetMap.ContainsKey(newIndex) == false)
{
Finished = true;
return;
}
var newval = IndexToOffsetMap[newIndex];
ProgramCounter.Value = newval;
}
