public void ExecuteOne()
{
Cycle++;
var opcodePos = Reg.ProgramCounter;
var opcode = (OpCode)_memory[Reg.ProgramCounter++];
var action = _opcodes[(int)opcode];
if (action.Action == null)
{
throw new Exception($"Unknown opcode: ${(int)opcode:X} ({opcode}) at pos ${opcodePos:X} ({opcodePos})");
}
#region OPCODE_DEBUGGING
CurrentExecutingOpcode = new CurrentExecutingOpcodeStruct();
CurrentExecutingOpcode.RegBefore = Reg;
CurrentExecutingOpcode.PC = (Word)opcodePos;
CurrentExecutingOpcode.Opcode = opcode;
if (Reg.ProgramCounter < _memory.Length)
{
CurrentExecutingOpcode.B1 = _memory[Reg.ProgramCounter];
}
if (Reg.ProgramCounter + 1 < _memory.Length)
{
CurrentExecutingOpcode.B2 = _memory[Reg.ProgramCounter + 1];
}
#endregion
try
{
action.Action.Invoke();
DebugPrintOpcode(CurrentExecutingOpcode);
}
catch (Exception exception)
{
DebugPrintOpcode(CurrentExecutingOpcode);
throw;
}
}
private void DebugPrintOpcode(CurrentExecutingOpcodeStruct ceo)
{
string addr;
var word = false;
switch (ceo.MemoryAccessType)
{
case MemoryAccessType.None:
addr = "".PadRight(10, ' ') + "; ";
break;
case MemoryAccessType.Immediate:
addr = ("#" + ceo.Data.ToString("X2")).PadRight(10, ' ') + "; ";
break;
case MemoryAccessType.Abs:
addr = ("$" + ceo.Address.ToString("X4")).PadRight(10, ' ') + "; #" + ceo.Data.ToString("X2");
word = true;
break;
case MemoryAccessType.AbsX:
addr = ("$" + ceo.Address.ToString("X4") + ",X").PadRight(10, ' ') + "; #" + ceo.Data.ToString("X2");
word = true;
break;
case MemoryAccessType.AbsY:
addr = ("$" + ceo.Address.ToString("X4") + ",Y").PadRight(10, ' ') + "; #" + ceo.Data.ToString("X2");
word = true;
break;
case MemoryAccessType.Zpg:
addr = ("$" + ceo.Address.ToString("X2")).PadRight(10, ' ') + "; #" + ceo.Data.ToString("X2");
break;
case MemoryAccessType.ZpgX:
addr = ("$" + ceo.Address.ToString("X2") + ",X").PadRight(10, ' ') + "; #" + ceo.Data.ToString("X2");
break;
case MemoryAccessType.ZpgY:
addr = ("$" + ceo.Address.ToString("X2") + ",Y").PadRight(10, ' ') + "; #" + ceo.Data.ToString("X2");
break;
case MemoryAccessType.Indirect:
addr = ("($" + ceo.Address.ToString("X4") + ")").PadRight(10, ' ') + "; #" + ceo.Data.ToString("X2");
word = true;
break;
case MemoryAccessType.XIndirect:
addr = ("($" + ceo.Address.ToString("X2") + ",X)").PadRight(10, ' ') + "; #" + ceo.Data.ToString("X2");
break;
case MemoryAccessType.IndirectY:
addr = ("($" + ceo.Address.ToString("X2") + "),Y").PadRight(10, ' ') + "; #" + ceo.Data.ToString("X2");
break;
default:
addr = "[UNKNOWN]";
break;
}
var str = ("$" + ceo.PC.ToString("X4")
+ " " + (
((int)ceo.Opcode).ToString("X2")
+ (ceo.MemoryAccessType != MemoryAccessType.None ? " " + ceo.B1.ToString("X2") : "")
+ (word ? " " + ceo.B2.ToString("X2") : "")
).PadRight(9, ' ')
+ _opcodeStr[(int)ceo.Opcode]
+ " " + addr.PadRight(20, ' ')
)
+ "A:" + Reg.A.ToString("X2") + (Reg.A != ceo.RegBefore.A ? "->" + ceo.RegBefore.A.ToString("X2") : " ")
+ " X:" + Reg.X.ToString("X2") + (Reg.X != ceo.RegBefore.X ? "->" + ceo.RegBefore.X.ToString("X2") : " ")
+ " Y:" + Reg.Y.ToString("X2") + (Reg.Y != ceo.RegBefore.Y ? "->" + ceo.RegBefore.Y.ToString("X2") : " ")
+ " SP:" + Reg.SP.ToString("X2") + (Reg.SP != ceo.RegBefore.SP ? "->" + ceo.RegBefore.SP.ToString("X2") : " ")
+ " "
+ (Reg.Flag.N ? (Reg.Flag.N == ceo.RegBefore.Flag.N ? "N" : "n") : ".")
+ (Reg.Flag.V ? (Reg.Flag.V == ceo.RegBefore.Flag.V ? "V" : "v") : ".")
+ " "
+ (Reg.Flag.B ? (Reg.Flag.B == ceo.RegBefore.Flag.B ? "B" : "b") : ".")
+ (Reg.Flag.D ? (Reg.Flag.D == ceo.RegBefore.Flag.D ? "D" : "d") : ".")
+ (Reg.Flag.I ? (Reg.Flag.I == ceo.RegBefore.Flag.I ? "I" : "i") : ".")
+ (Reg.Flag.Z ? (Reg.Flag.Z == ceo.RegBefore.Flag.Z ? "Z" : "z") : ".")
+ (Reg.Flag.C ? (Reg.Flag.C == ceo.RegBefore.Flag.C ? "C" : "c") : ".")
+ " " + ceo.Opcode
;
Trace.WriteLine(str);
}
