private void instruction_0xD_handler(CPUInstruction instruction, CPU cpu, RAM ram, Screen screen, Keyboard keyboard)
{
// Display n-byte sprite starting at memory location I at (Vx, Vy), set VF = collision.
byte[] sprites = ram.Read(cpu.I, (uint)cpu.I + instruction.N - 1);
uint x = cpu.VX[instruction.X];
uint y = cpu.VX[instruction.Y];
cpu.VX[0xF] = screen.XorPixel(sprites, x, y) ? (byte)1 : (byte)0;
}
private void instruction_0xF_handler(CPUInstruction instruction, CPU cpu, RAM ram, Screen screen, Keyboard keyboard)
{
// Set Vx = delay timer value.
if (instruction.KK == 0x07)
{
cpu.VX[instruction.X] = cpu.DelayTimer;
return;
}
// Wait for a key press, store the value of the key in Vx.
// I THINK I'VE FOUND A F*****G ERROR!!!!
if (instruction.KK == 0x0A)
{
/*
* bool pressedKey = false;
* while (!pressedKey)
* {
* for (byte key = 0; key <= 0xF; ++key)
* {
* pressedKey = keyboard.IsKeyPressed(key);
* if (pressedKey)
* {
* cpu.VX[instruction.X] = key;
* break;
* }
* }
* }*/
bool pressedKey = false;
for (byte key = 0; key <= 0xF; ++key)
{
pressedKey = keyboard.IsKeyPressed(key);
if (pressedKey)
{
cpu.VX[instruction.X] = key;
break;
}
}
if (!pressedKey)
{
cpu.PC -= 2;
}
return;
}
// Set delay timer = Vx.
if (instruction.KK == 0x15)
{
cpu.DelayTimer = cpu.VX[instruction.X];
return;
}
// Set sound timer = Vx.
if (instruction.KK == 0x18)
{
cpu.SoundTimer = cpu.VX[instruction.X];
return;
}
// Set I = I + Vx.
if (instruction.KK == 0x1E)
{
cpu.I += cpu.VX[instruction.X];
return;
}
// Set I = location of sprite for digit Vx.
if (instruction.KK == 0x29)
{
cpu.I = (ushort)(RAM.SPRITES_OFFSET + cpu.VX[instruction.X] * RAM.SPRITE_SIZE);
return;
}
// Store BCD representation of Vx in memory locations I, I+1, and I+2.
if (instruction.KK == 0x33)
{
byte number = cpu.VX[instruction.X];
byte hundredsDigit = (byte)(Math.Floor((double)number / 100) % 10);
byte tensDigit = (byte)(Math.Floor((double)number / 10) % 10);
byte onesDigit = (byte)(number % 10);
byte[] data = { hundredsDigit, tensDigit, onesDigit };
ram.LoadToMemory(data, cpu.I);
return;
}
// Store registers V0 through Vx in memory starting at location I.
if (instruction.KK == 0x55)
{
byte[] data = new byte[instruction.X + 1];
for (uint i = 0; i <= instruction.X; ++i)
{
data[i] = cpu.VX[i];
}
ram.LoadToMemory(data, cpu.I);
return;
}
// Read registers V0 through Vx from memory starting at location I.
if (instruction.KK == 0x65)
{
byte[] data = ram.Read(cpu.I, (uint)cpu.I + instruction.X);
for (uint i = 0; i < data.Length; ++i)
{
cpu.VX[i] = data[i];
}
return;
}
}
