public byte ReadByte(ushort address)
{
if (address == 0xFF00)
{
// request latest input from interface
GBCoreInput newInputState = _inputSource.PollInput();
// check to see if a button is pressed in this input state
// that was not pressed the previous state, if so, raise the
// input interrupt
if (ButtonPressed(_inputState, newInputState))
{
_interruptController.RequestInterrupt(Interrupt.Input);
}
_inputState = newInputState;
int p14Value = 0x0F;
int p15Value = 0x0F;
if (_p14)
{
p14Value = (_inputState.Down ? 0 : (1 << 3)) |
(_inputState.Up ? 0 : (1 << 2)) |
(_inputState.Left ? 0 : (1 << 1)) |
(_inputState.Right ? 0 : (1 << 0));
}
if (_p15)
{
p15Value = (_inputState.Start ? 0 : (1 << 3)) |
(_inputState.Select ? 0 : (1 << 2)) |
(_inputState.B ? 0 : (1 << 1)) |
(_inputState.A ? 0 : (1 << 0));
}
return((byte)(0xC0 | _inputSelect | (p14Value & p15Value)));
}
else
{
throw new ArgumentException("Invalid memory address passed to InputController.ReadByte", "address");
}
}
private bool ButtonPressed(GBCoreInput previousInputState, GBCoreInput newInputState)
{
// check each button, if any of them were not pressed previously and they are
// now we return true
if ((!previousInputState.Up && newInputState.Up) ||
(!previousInputState.Down && newInputState.Down) ||
(!previousInputState.Left && newInputState.Left) ||
(!previousInputState.Right && newInputState.Right) ||
(!previousInputState.A && newInputState.A) ||
(!previousInputState.B && newInputState.B) ||
(!previousInputState.Start && newInputState.Start) ||
(!previousInputState.Select && newInputState.Select))
{
return(true);
}
else
{
return(false);
}
}
