67 lines
1.4 KiB
C#
67 lines
1.4 KiB
C#
using BizHawk.Common;
|
|
using BizHawk.Common.NumberExtensions;
|
|
|
|
namespace BizHawk.Emulation.Cores.Nintendo.NES
|
|
{
|
|
// 64-in-1
|
|
// http://wiki.nesdev.com/w/index.php/INES_Mapper_204
|
|
public class Mapper204 : NES.NESBoardBase
|
|
{
|
|
private int _reg1, _reg2;
|
|
|
|
private int prg_mask_16k, chr_mask_8k;
|
|
|
|
public override bool Configure(NES.EDetectionOrigin origin)
|
|
{
|
|
switch (Cart.board_type)
|
|
{
|
|
case "MAPPER204":
|
|
break;
|
|
default:
|
|
return false;
|
|
}
|
|
|
|
prg_mask_16k = Cart.prg_size / 16 - 1;
|
|
chr_mask_8k = Cart.chr_size / 8 - 1;
|
|
|
|
return true;
|
|
}
|
|
|
|
public override void SyncState(Serializer ser)
|
|
{
|
|
base.SyncState(ser);
|
|
ser.Sync("reg1", ref _reg1);
|
|
ser.Sync("reg2", ref _reg2);
|
|
}
|
|
|
|
public override void WritePRG(int addr, byte value)
|
|
{
|
|
_reg1 = addr & 0x6;
|
|
_reg2 = _reg1 + ((_reg1 == 0x6) ? 0 : (addr & 1));
|
|
_reg1 = _reg1 + ((_reg1 == 0x6) ? 1 : (addr & 1));
|
|
|
|
SetMirrorType(addr.Bit(0) ? EMirrorType.Vertical : EMirrorType.Horizontal);
|
|
}
|
|
|
|
public override byte ReadPRG(int addr)
|
|
{
|
|
if (addr < 0x4000)
|
|
{
|
|
return ROM[((_reg2 & prg_mask_16k) * 0x4000) + (addr & 0x3FFF)];
|
|
}
|
|
|
|
return ROM[((_reg1 & prg_mask_16k) * 0x4000) + (addr & 0x3FFF)];
|
|
}
|
|
|
|
public override byte ReadPPU(int addr)
|
|
{
|
|
if (addr < 0x2000)
|
|
{
|
|
return VROM[((_reg2 & chr_mask_8k) * 0x2000) + (addr & 0x1FFF)];
|
|
}
|
|
|
|
return base.ReadPPU(addr);
|
|
}
|
|
}
|
|
}
|