BizHawk/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/NES.iNES.cs

120 lines
2.9 KiB
C#

using System;
using System.IO;
using System.Linq;
using System.Text;
using BizHawk.Common.NumberExtensions;
namespace BizHawk.Emulation.Cores.Nintendo.NES
{
partial class NES
{
private static int iNES2Wram(int i)
{
if (i == 0) return 0;
if (i == 15) throw new InvalidDataException();
return 1 << (i + 6);
}
public static bool DetectFromINES(byte[] data, out CartInfo Cart, out CartInfo CartV2)
{
byte[] ID = new byte[4];
Buffer.BlockCopy(data, 0, ID, 0, 4);
if (!ID.SequenceEqual(Encoding.ASCII.GetBytes("NES\x1A")))
{
Cart = null;
CartV2 = null;
return false;
}
if ((data[7] & 0x0c) == 0x08)
{
// process as iNES v2
CartV2 = new CartInfo
{
PrgSize = data[4] | data[9] << 8 & 0xf00,
ChrSize = data[5] | data[9] << 4 & 0xf00
};
CartV2.PrgSize *= 16;
CartV2.ChrSize *= 8;
CartV2.WramBattery = (data[6] & 2) != 0; // should this be respected in v2 mode??
int wrambat = iNES2Wram(data[10] >> 4);
int wramnon = iNES2Wram(data[10] & 15);
CartV2.WramBattery |= wrambat > 0;
// fixme - doesn't handle sizes not divisible by 1024
CartV2.WramSize = (short)((wrambat + wramnon) / 1024);
int mapper = data[6] >> 4 | data[7] & 0xf0 | data[8] << 8 & 0xf00;
int submapper = data[8] >> 4;
CartV2.BoardType = $"MAPPER{mapper:d4}-{submapper:d2}";
int vrambat = iNES2Wram(data[11] >> 4);
int vramnon = iNES2Wram(data[11] & 15);
// hopefully a game with battery backed vram understands what to do internally
CartV2.WramBattery |= vrambat > 0;
CartV2.VramSize = (vrambat + vramnon) / 1024;
CartV2.InesMirroring = data[6] & 1 | data[6] >> 2 & 2;
switch (CartV2.InesMirroring)
{
case 0: CartV2.PadV = 1; break;
case 1: CartV2.PadH = 1; break;
}
switch (data[12] & 1)
{
case 0:
CartV2.System = "NES-NTSC";
break;
case 1:
CartV2.System = "NES-PAL";
break;
}
if ((data[6] & 4) != 0)
CartV2.TrainerSize = 512;
}
else
{
CartV2 = null;
}
// process as iNES v1
// the DiskDude cleaning is no longer; get better roms
Cart = new CartInfo
{
PrgSize = data[4],
ChrSize = data[5]
};
if (Cart.PrgSize == 0)
Cart.PrgSize = 256;
Cart.PrgSize *= 16;
Cart.ChrSize *= 8;
Cart.WramBattery = (data[6] & 2) != 0;
Cart.WramSize = 8; // should be data[8], but that never worked
{
int mapper = data[6] >> 4 | data[7] & 0xf0;
Cart.BoardType = $"MAPPER{mapper:d3}";
}
Cart.VramSize = Cart.ChrSize > 0 ? 0 : 8;
Cart.InesMirroring = data[6] & 1 | data[6] >> 2 & 2;
switch (Cart.InesMirroring)
{
case 0: Cart.PadV = 1; break;
case 1: Cart.PadH = 1; break;
}
if (data[6].Bit(2))
Cart.TrainerSize = 512;
return true;
}
}
}