private bool SKP(ushort instruction)
{
var value = ParserFunctions.GetValue(instruction);
var x = ParserFunctions.GetX(instruction);
var key = Register[x];
switch (value)
{
case 0x9e:
if (keyboard.GetValue(key))
{
InstructionPointer += 2;
}
break;
case 0xa1:
if (!keyboard.GetValue(key))
{
InstructionPointer += 2;
break;
}
break;
default:
throw new InvalidOperationException();
}
return(false);
}
private bool ADD(ushort instruction)
{
int register = ParserFunctions.GetX(instruction);
byte value = ParserFunctions.GetValue(instruction);
Register[register] += value;
return(false);
}
private bool LD(ushort instruction)
{
byte x = ParserFunctions.GetX(instruction);
var value = ParserFunctions.GetValue(instruction);
Register[x] = value;
return(false);
}
private bool RND(ushort instruction)
{
byte randomValue = RandomFunc();
var register = ParserFunctions.GetX(instruction);
var mask = ParserFunctions.GetValue(instruction);
Register[register] = (byte)(randomValue & mask);
return(false);
}
private bool REG(ushort instruction)
{
byte subcommand = ParserFunctions.GetSubCommand(instruction);
var command = RegisterCommands[subcommand];
var regX = ParserFunctions.GetX(instruction);
var regY = ParserFunctions.GetY(instruction);
command(regX, regY);
return(false);
}
private bool SE(ushort instruction)
{
byte x = ParserFunctions.GetX(instruction);
byte regValue = Register[x];
byte opValue = ParserFunctions.GetValue(instruction);
if (regValue == opValue)
{
InstructionPointer += 2;
}
return(false);
}
private bool SNEV(ushort instruction)
{
var regX = ParserFunctions.GetX(instruction);
var regY = ParserFunctions.GetY(instruction);
var regValueX = Register[regX];
var regValueY = Register[regY];
if (regValueX != regValueY)
{
InstructionPointer += 2;
}
return(true);
}
private bool SEV(ushort instruction)
{
byte x = ParserFunctions.GetX(instruction);
byte regValueX = Register[x];
byte y = ParserFunctions.GetY(instruction);
byte regValueY = Register[y];
if (regValueX == regValueY)
{
InstructionPointer += 2;
}
return(false);
}
private bool DRW(ushort instruction)
{
var Vx = ParserFunctions.GetX(instruction);
var Vy = ParserFunctions.GetY(instruction);
var x = Register[Vx];
var y = Register[Vy];
var count = ParserFunctions.GetSubCommand(instruction);
byte[] sprite = new byte[count];
for (ushort i = 0; i < count; i++)
{
sprite[i] = memory.GetValue((ushort)(AddressRegister + i));
}
var collision = SetSprite(x, y, sprite, count);
Register[0xF] = (byte)collision;
// Draw screen
display.Print();
return(false);
}
bool LDS(ushort instruction)
{
var register = ParserFunctions.GetX(instruction);
var subcommand = ParserFunctions.GetValue(instruction);
switch (subcommand)
{
case 0x15:
DelayTimer.Value = Register[register];
break;
case 0x07:
Register[register] = DelayTimer.Value;
break;
case 0x18:
SoundTimer.Value = Register[register];
break;
case 0x1e:
AddressRegister += Register[register];
break;
case 0x29:
AddressRegister = (ushort)(Register[register] * SPRITE_SIZE);
break;
case 0x33:
byte value = Register[register];
byte hundreds = (byte)(value / 100);
byte tens = (byte)((value - (hundreds * 100)) / 10);
byte ones = (byte)(value - ((hundreds * 100) + (tens * 10)));
memory.SetValue(AddressRegister, hundreds);
memory.SetValue((ushort)(AddressRegister + 1), tens);
memory.SetValue((ushort)(AddressRegister + 2), ones);
break;
case 0x55:
for (int i = 0; i <= register; i++)
{
ushort address = (ushort)(AddressRegister + i);
memory.SetValue(address, Register[i]);
}
break;
case 0x0a:
var key = keyboard.WaitForValue();
Register[register] = key;
break;
case 0x65:
for (int i = 0; i <= register; i++)
{
ushort address = (ushort)(AddressRegister + i);
Register[i] = memory.GetValue(address);
}
break;
default:
throw new NotImplementedException(string.Format("Subcommand {0:x} not implemented", subcommand));
}
return(false);
}