public Z80(Device d)
{
_d = d;
_cycles = 0;
_r = new Registers();
_ime = InterruptMasterEnable.Disabled;
_halted = false;
}
void Reti()
{
_ime = InterruptMasterEnable.Enabled;
Ret();
}
void Ei()
{
_ime = InterruptMasterEnable.Enabling;
}
void Di()
{
_ime = InterruptMasterEnable.Disabled;
}
public int Step()
{
_cycles = 0;
if (!_halted)
{
var opcode = DecodeInstruction();
Decode(opcode);
}
else
{
InternalDelay();
}
if (_d.IRQ.CanServiceInterrupts)
{
_halted = false;
if (_ime == InterruptMasterEnable.Enabled)
{
if (_d.IRQ.CanHandleInterrupt(InterruptFlags.VBL))
{
Restart(0x40);
_ime = InterruptMasterEnable.Disabled;
_d.IRQ.DisableInterrupt(InterruptFlags.VBL);
}
else if (_d.IRQ.CanHandleInterrupt(InterruptFlags.STAT))
{
Restart(0x48);
_ime = InterruptMasterEnable.Disabled;
_d.IRQ.DisableInterrupt(InterruptFlags.STAT);
}
else if (_d.IRQ.CanHandleInterrupt(InterruptFlags.Timer))
{
Restart(0x50);
_ime = InterruptMasterEnable.Disabled;
_d.IRQ.DisableInterrupt(InterruptFlags.Timer);
}
else if (_d.IRQ.CanHandleInterrupt(InterruptFlags.Serial))
{
Restart(0x58);
_ime = InterruptMasterEnable.Disabled;
_d.IRQ.DisableInterrupt(InterruptFlags.Serial);
}
else if (_d.IRQ.CanHandleInterrupt(InterruptFlags.Joypad))
{
Restart(0x60);
_ime = InterruptMasterEnable.Disabled;
_d.IRQ.DisableInterrupt(InterruptFlags.Joypad);
}
}
}
if (_cycles >= 4 && _ime == InterruptMasterEnable.Enabling)
{
_ime = InterruptMasterEnable.Enabled;
}
return(_cycles);
}
