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

116 lines
3.7 KiB
C#

using System.IO;
using BizHawk.Common;
namespace BizHawk.Emulation.Cores.Nintendo.NES
{
partial class NES
{
/// <summary>
/// attempts to classify a rom based on iNES header information.
/// this used to be way more complex. but later, we changed to have a board class implement a "MAPPERXXX" virtual board type and all hacks will be in there
/// so theres nothing to do here but pick the board type corresponding to the cart
/// </summary>
static class iNESBoardDetector
{
public static string Detect(CartInfo cartInfo)
{
return string.Format("MAPPER{0:d3}",cartInfo.mapper);
}
}
unsafe struct iNES_HEADER
{
public fixed byte ID[4]; /*NES^Z*/
public byte ROM_size;
public byte VROM_size;
public byte ROM_type;
public byte ROM_type2;
public byte wram_size;
public byte flags9, flags10;
public byte zero11, zero12, zero13, zero14, zero15;
public bool CheckID()
{
fixed (iNES_HEADER* self = &this)
return 0 == Util.memcmp(self, "NES\x1A", 4);
}
//some cleanup code recommended by fceux
public void Cleanup()
{
fixed (iNES_HEADER* self = &this)
{
if (0 == Util.memcmp((byte*)(self) + 0x7, "DiskDude", 8))
{
Util.memset((byte*)(self) + 0x7, 0, 0x9);
}
if (0 == Util.memcmp((byte*)(self) + 0x7, "demiforce", 9))
{
Util.memset((byte*)(self) + 0x7, 0, 0x9);
}
if (0 == Util.memcmp((byte*)(self) + 0x8, "blargg", 6)) //found a test rom with this in there, mucking up the wram size
{
Util.memset((byte*)(self) + 0x8, 0, 6);
}
if (0 == Util.memcmp((byte*)(self) + 0xA, "Ni03", 4))
{
if (0 == Util.memcmp((byte*)(self) + 0x7, "Dis", 3))
Util.memset((byte*)(self) + 0x7, 0, 0x9);
else
Util.memset((byte*)(self) + 0xA, 0, 0x6);
}
}
}
public CartInfo Analyze(TextWriter report)
{
var ret = new CartInfo();
ret.game = new NESGameInfo();
int mapper = (ROM_type >> 4);
mapper |= (ROM_type2 & 0xF0);
ret.mapper = (byte)mapper;
int mirroring = (ROM_type & 1);
if ((ROM_type & 8) != 0) mirroring += 2;
if (mirroring == 0) ret.pad_v = 1;
else if (mirroring == 1) ret.pad_h = 1;
ret.inesmirroring = mirroring;
ret.prg_size = (short)(ROM_size * 16);
if (ret.prg_size == 0)
ret.prg_size = 256 * 16;
ret.chr_size = (short)(VROM_size * 8);
ret.wram_battery = (ROM_type & 2) != 0;
if(wram_size != 0 || flags9 != 0 || flags10 != 0 || zero11 != 0 || zero12 != 0 || zero13 != 0 || zero14 != 0 || zero15 != 0)
{
report.WriteLine("Looks like you have an iNES 2.0 header, or some other kind of weird garbage.");
report.WriteLine("We haven't bothered to support iNES 2.0.");
report.WriteLine("We might, if we can find anyone who uses it. Let us know.");
}
ret.wram_size = (short)(wram_size * 8);
//0 is supposed to mean 8KB (for compatibility, as this is an extension to original iNES format)
if (ret.wram_size == 0)
{
report.WriteLine("iNES wr=0 interpreted as wr=8");
ret.wram_size = 8;
}
//iNES wants us to assume that no chr -> 8KB vram
if (ret.chr_size == 0) ret.vram_size = 8;
//let's not put a lot of hacks in here. that's what the databases are for.
//for example of one not to add: videomation hack to change vram = 8 -> 16
string mirror_memo = mirroring == 0 ? "horz" : (mirroring == 1 ? "vert" : "4screen");
report.WriteLine("map={0},pr={1},ch={2},wr={3},vr={4},ba={5},mir={6}({7})", ret.mapper, ret.prg_size, ret.chr_size, ret.wram_size, ret.vram_size, ret.wram_battery ? 1 : 0, mirroring, mirror_memo);
return ret;
}
}
}
}