178 lines
3.8 KiB
C#
178 lines
3.8 KiB
C#
using BizHawk.Common;
|
|
using BizHawk.Common.NumberExtensions;
|
|
|
|
namespace BizHawk.Emulation.Cores.Nintendo.NES
|
|
{
|
|
internal sealed class Mapper253 : NesBoardBase
|
|
{
|
|
private byte[] _prg = new byte[2];
|
|
private byte[] chrlo = new byte[8];
|
|
private byte[] chrhi = new byte[8];
|
|
private bool _vLock;
|
|
private int _irqLatch, _irqClock, _irqCount;
|
|
private bool _irqA;
|
|
|
|
private int _prgBankMask8K, _chrBankMask1k;
|
|
|
|
public override bool Configure(EDetectionOrigin origin)
|
|
{
|
|
//analyze board type
|
|
switch (Cart.BoardType)
|
|
{
|
|
case "MAPPER253":
|
|
break;
|
|
default:
|
|
return false;
|
|
}
|
|
|
|
_prgBankMask8K = Cart.PrgSize / 8 - 1;
|
|
_chrBankMask1k = Cart.ChrSize - 1;
|
|
|
|
return true;
|
|
}
|
|
|
|
public override void SyncState(Serializer ser)
|
|
{
|
|
base.SyncState(ser);
|
|
ser.Sync("preg", ref _prg, false);
|
|
ser.Sync(nameof(chrlo), ref chrlo, false);
|
|
ser.Sync(nameof(chrhi), ref chrhi, false);
|
|
}
|
|
|
|
public override void ClockCpu()
|
|
{
|
|
if (_irqA)
|
|
{
|
|
_irqClock += 3;
|
|
if (_irqClock >= 341)
|
|
{
|
|
_irqClock -= 341;
|
|
_irqCount++;
|
|
if (_irqCount == 0x100)
|
|
{
|
|
IrqSignal = true;
|
|
_irqCount = _irqLatch;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
public override void WritePrg(int addr, byte value)
|
|
{
|
|
addr += 0x8000;
|
|
if ((addr >= 0xB000) && (addr <= 0xE00C))
|
|
{
|
|
var ind = ((((addr & 8) | (addr >> 8)) >> 3) + 2) & 7;
|
|
var sar = addr & 4;
|
|
var clo = (chrlo[ind] & (0xF0 >> sar)) | ((value & 0x0F) << sar);
|
|
chrlo[ind] = (byte)clo;
|
|
if (ind == 0)
|
|
{
|
|
if (clo == 0xc8)
|
|
_vLock = false;
|
|
else if (clo == 0x88)
|
|
_vLock = true;
|
|
}
|
|
if (sar > 0)
|
|
chrhi[ind] = (byte)(value >> 4);
|
|
}
|
|
else
|
|
{
|
|
switch (addr)
|
|
{
|
|
case 0x8010: _prg[0] = value; break;
|
|
case 0xA010: _prg[1] = value; break;
|
|
case 0x9400: SetMirroring(value); break;
|
|
|
|
case 0xF000: IrqSignal = false; _irqLatch &= 0xF0; _irqLatch |= value & 0xF; break;
|
|
case 0xF004: IrqSignal = false; _irqLatch &= 0x0F; _irqLatch |= value << 4; break;
|
|
case 0xF008: IrqSignal = false; _irqClock = 0; _irqCount = _irqLatch; _irqA = value.Bit(1); break;
|
|
}
|
|
}
|
|
}
|
|
|
|
private void SetMirroring(int mirr)
|
|
{
|
|
switch(mirr & 3)
|
|
{
|
|
case 0: SetMirrorType(EMirrorType.Vertical); break;
|
|
case 1: SetMirrorType(EMirrorType.Horizontal); break;
|
|
case 2: SetMirrorType(EMirrorType.OneScreenA); break;
|
|
case 3: SetMirrorType(EMirrorType.OneScreenB); break;
|
|
}
|
|
}
|
|
|
|
public override byte ReadPrg(int addr)
|
|
{
|
|
int bank;
|
|
|
|
if (addr < 0x2000)
|
|
{
|
|
bank = _prg[0] & _prgBankMask8K;
|
|
}
|
|
else if (addr < 0x4000)
|
|
{
|
|
bank = _prg[1] & _prgBankMask8K;
|
|
}
|
|
else if (addr < 0x6000)
|
|
{
|
|
bank = _prgBankMask8K - 1;
|
|
}
|
|
else
|
|
{
|
|
bank = _prgBankMask8K;
|
|
}
|
|
|
|
|
|
return Rom[(bank << 13) + (addr & 0x1FFF)];
|
|
}
|
|
|
|
public override byte ReadPpu(int addr)
|
|
{
|
|
|
|
if (addr < 0x2000)
|
|
{
|
|
int x = (addr >> 10) & 7;
|
|
var chr = chrlo[x] | (chrhi[x] << 8);
|
|
int bank = (chr & _chrBankMask1k) << 10;
|
|
|
|
if ((chrlo[x] == 4 || chrlo[x] == 5) && !_vLock)
|
|
{
|
|
bank = chr & 1;
|
|
return Vram[(bank << 10) + (addr & 0x3FF)];
|
|
}
|
|
else
|
|
{
|
|
return Vrom[bank + (addr & 0x3FF)];
|
|
}
|
|
|
|
}
|
|
|
|
return base.ReadPpu(addr);
|
|
}
|
|
|
|
public override void WritePpu(int addr, byte value)
|
|
{
|
|
if (addr < 0x2000)
|
|
{
|
|
if (Vram != null)
|
|
{
|
|
int x = (addr >> 10) & 7;
|
|
var chr = chrlo[x] | (chrhi[x] << 8);
|
|
int bank = (chr & _chrBankMask1k) << 10;
|
|
|
|
if ((chrlo[x] == 4 || chrlo[x] == 5) && !_vLock)
|
|
{
|
|
bank = chr & 1;
|
|
Vram[(bank << 10) + (addr & 0x3FF)]=value;
|
|
}
|
|
}
|
|
}
|
|
else
|
|
{
|
|
NES.CIRAM[ApplyMirroring(addr)] = value;
|
|
}
|
|
}
|
|
}
|
|
}
|