64 lines
1.2 KiB
C#
64 lines
1.2 KiB
C#
|
using System;
|
|||
|
|
using System.Collections.Generic;
|
|||
|
|
using System.Linq;
|
|||
|
|
using System.Text;
|
|||
|
|
using System.Threading.Tasks;
|
|||
|
|
|
|||
|
|
namespace Essgee.Emulation.CPU
|
|||
|
|
{
|
|||
|
|
public class SM83CGB : SM83
|
|||
|
|
{
|
|||
|
|
// TODO: better way of implementing this?
|
|||
|
|
public bool IsDoubleSpeed { get; private set; }
|
|||
|
|
|
|||
|
|
public SM83CGB(MemoryReadDelegate memoryRead, MemoryWriteDelegate memoryWrite) : base(memoryRead, memoryWrite) { }
|
|||
|
|
|
|||
|
|
protected override void EnterHaltState()
|
|||
|
|
{
|
|||
|
|
if (ime)
|
|||
|
|
{
|
|||
|
|
halt = true;
|
|||
|
|
pc--;
|
|||
|
|
}
|
|||
|
|
else
|
|||
|
|
{
|
|||
|
|
if ((memoryReadDelegate(0xFF0F) & memoryReadDelegate(0xFFFF) & 0x1F) != 0)
|
|||
|
|
currentCycles += 8;
|
|||
|
|
else
|
|||
|
|
halt = true;
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
protected override void Stop()
|
|||
|
|
{
|
|||
|
|
pc++;
|
|||
|
|
|
|||
|
|
// Perform speed switch; get IO register value
|
|||
|
|
var key1 = memoryReadDelegate(0xFF4D);
|
|||
|
|
|
|||
|
|
// Is speed switch pending?
|
|||
|
|
if ((key1 & 0b1) != 0)
|
|||
|
|
{
|
|||
|
|
// Clear pending flag
|
|||
|
|
key1 &= 0xFE;
|
|||
|
|
|
|||
|
|
if (((key1 >> 7) & 0b1) != 0)
|
|||
|
|
{
|
|||
|
|
// Was double speed, now normal speed
|
|||
|
|
key1 &= 0x7F;
|
|||
|
|
IsDoubleSpeed = false;
|
|||
|
|
}
|
|||
|
|
else
|
|||
|
|
{
|
|||
|
|
// Was normal speed, now double speed
|
|||
|
|
key1 |= 0x80;
|
|||
|
|
IsDoubleSpeed = true;
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
// Write register value
|
|||
|
|
memoryWriteDelegate(0xFF4D, key1);
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
}
|