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

108 lines
2.8 KiB
C#

using System;
using System.IO;
using System.Linq;
using System.Text;
using BizHawk.Common;
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();
CartV2.prg_size = data[4] | data[9] << 8 & 0xf00;
CartV2.chr_size = data[5] | data[9] << 4 & 0xf00;
CartV2.prg_size *= 16;
CartV2.chr_size *= 8;
CartV2.wram_battery = (data[6] & 2) != 0; // should this be respected in v2 mode??
int wrambat = iNES2Wram(data[10] >> 4);
int wramnon = iNES2Wram(data[10] & 15);
CartV2.wram_battery |= wrambat > 0;
// fixme - doesn't handle sizes not divisible by 1024
CartV2.wram_size = (short)((wrambat + wramnon) / 1024);
int mapper = data[6] >> 4 | data[7] & 0xf0 | data[8] << 8 & 0xf00;
int submapper = data[8] >> 4;
CartV2.board_type = string.Format("MAPPER{0:d4}-{1:d2}", mapper, submapper);
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.wram_battery |= vrambat > 0;
CartV2.vram_size = (vrambat + vramnon) / 1024;
CartV2.inesmirroring = data[6] & 1 | data[6] >> 2 & 2;
switch (CartV2.inesmirroring)
{
case 0: CartV2.pad_v = 1; break;
case 1: CartV2.pad_h = 1; break;
}
}
else
{
CartV2 = null;
}
// process as iNES v1
// the DiskDude cleaning is no longer; get better roms
Cart = new CartInfo();
Cart.prg_size = data[4];
Cart.chr_size = data[5];
if (Cart.prg_size == 0)
Cart.prg_size = 256;
Cart.prg_size *= 16;
Cart.chr_size *= 8;
Cart.wram_battery = (data[6] & 2) != 0;
Cart.wram_size = 8; // should be data[8], but that never worked
{
int mapper = data[6] >> 4 | data[7] & 0xf0;
Cart.board_type = string.Format("MAPPER{0:d3}", mapper);
}
Cart.vram_size = Cart.chr_size > 0 ? 0 : 8;
Cart.inesmirroring = data[6] & 1 | data[6] >> 2 & 2;
switch (Cart.inesmirroring)
{
case 0: Cart.pad_v = 1; break;
case 1: Cart.pad_h = 1; break;
}
if (data[6].Bit(2))
Console.WriteLine("DANGER: According to the flags, this iNES has a trainer in it! We don't support this garbage.");
return true;
}
}
}