private void Execute(Opcode param)
{
switch (param.Nibble)
{
case 0x0000:
if (param.Value == 0x00e0)
{
display.ClearDisplay();
}
else if (param.Value == 0x00ee)
{
var address = ram.ReturnFromSubroutine();
register.JumpToAddress(address);
break;
}
else
{
throw new InvalidOperationException("opcode not found");
}
break;
case 0x1000:
register.JumpToAddress(param.NNN);
break;
case 0x2000:
ram.CallSubroutine(register.PC);
register.JumpToAddress(param.NNN);
break;
case 0x3000:
if (register[param.X] == param.NN)
{
register.IncrementPC();
}
break;
case 0x4000:
if (register[param.X] != param.NN)
{
register.IncrementPC();
}
break;
case 0x5000:
if (register[param.X] == register[param.Y])
{
register.IncrementPC();
}
break;
case 0x6000:
register.StoreValue(param.X, param.NN);
break;
case 0x7000:
register.IncrementRegisterValue(param.X, param.NN);
break;
case 0x8000:
byte last = (byte)(param.Value & 0x000F);
switch (last)
{
case 0: register.StoreValue(param.X, register[param.Y]); break;
case 1: register.CalculateRegistersAndStoreValue(param.X, param.X, param.Y, BitOperationType.OR); break;
case 2: register.CalculateRegistersAndStoreValue(param.X, param.X, param.Y, BitOperationType.AND); break;
case 3: register.CalculateRegistersAndStoreValue(param.X, param.X, param.Y, BitOperationType.XOR); break;
case 4:
register.StoreValueOnRegister0xF((byte)(register[param.X] + register[param.Y] > 255 ? 1 : 0));
register.StoreValue(param.X, (byte)((register[param.X] + register[param.Y]) & 0x00FF));
break;
case 5:
register.StoreValueOnRegister0xF((byte)(register[param.X] > register[param.Y] ? 1 : 0));
register.StoreValue(param.X, (byte)((register[param.X] - register[param.Y]) & 0x00FF));
break;
case 6:
register.StoreValueOnRegister0xF((byte)(register[param.X] & 0x0001));
register.StoreValue(param.X, (byte)(register[param.X] >> 1));
break;
case 7:
register.StoreValueOnRegister0xF((byte)(register[param.Y] > register[param.X] ? 1 : 0));
register.StoreValue(param.X, (byte)((register[param.Y] - register[param.X]) & 0x00FF));
break;
case 0xE:
register.StoreValueOnRegister0xF((byte)((register[param.X] & 0x80) == 0x80 ? 1 : 0));
register.StoreValue(param.X, (byte)(register[param.X] << 1));
break;
default:
throw new InvalidOperationException("opcode not found");
}
break;
case 0x9000:
if (register[param.X] != register[param.Y])
{
register.IncrementPC();
}
break;
case 0xA000:
register.SetRegisterI(param.NNN); break;
case 0xB000:
register.JumpToAddress((ushort)(register[0] + param.NNN)); return;
case 0xC000:
register.StoreValue(param.X, (byte)((byte)Random.Next(0, byte.MaxValue) & param.NN));
break;
case 0xE000:
last = (byte)(param.Value & 0x000F);
switch (last)
{
case 14:
if (register[param.X] == Keyboard)
{
register.IncrementPC();
}
break;
case 1:
if (register[param.X] != Keyboard)
{
register.IncrementPC();
}
break;
default:
throw new InvalidOperationException("opcode not found");
}
break;
case 0xD000:
var sprites = ram.GetValues(register.I, param.N);
display.Draw(sprites, register[param.X], register[param.Y], out var overridePixel);
register.StoreValueOnRegister0xF(overridePixel);
break;
case 0xF000:
last = (byte)(param.Value & 0x00FF);
switch (last)
{
case 0x7: //FX07
register.StoreValue(param.X, timer.DelayTimer);
break;
case 0x0A:
WaitingForKeyboardEvent.WaitOne();
register.StoreValue(param.X, Keyboard);
break;
case 0x15:
timer.SetTimer(TimerType.Delay, register[param.X]);
break;
case 0x18: //FX18
timer.SetTimer(TimerType.Sound, register[param.X]);
break;
case 0x1E:
register.IncreaseRegisterI(register[param.X]);
break;
case 0x29:
register.SetRegisterI(ram.GetFontAddress(register[param.X]));
break;
case 0x33:
var bcd = BCD.GetBytes(register[param.X]);
ram.CopyValuesToRam(bcd, register.I);
break;
case 0x55:
ram.CopyValuesToRam(register.GetRegisters(0, param.X), register.I);
break;
case 0x65:
register.CopyValuesToRegisters(ram.GetValues(register.I, param.X, inclusive: true), 0);
break;
default:
throw new InvalidOperationException("opcode not found");
}
break;
default:
throw new Exception("opcode not found");
}
Thread.Sleep(1);
}
public void LoadProgram(byte[] program)
{
ram.CopyValuesToRam(program, 0x200);
ProgramLoaded = true;
}
