SabreTools/SabreTools.Serialization
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Add NES cart reader

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This commit is contained in:
Matt Nadareski
2026-03-06 11:03:54 -05:00
parent 1875adfe5f
commit 9e68cf7abe
4 changed files with 165 additions and 2 deletions
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7
SabreTools.Serialization/Models/NES/Cart.cs
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@@ -35,7 +35,12 @@ namespace SabreTools.Data.Models.NES
/// <summary>
/// PlayChoice PROM, if present (16 bytes Data, 16 bytes CounterOut)
/// </summary>
/// <remarks>This is often missing; see PC10 ROM-Images for details</remarks>
/// <remarks>
/// This is often missing; see PC10 ROM-Images for details
/// 16 bytes RP5H01 PROM Data output (needed to decrypt the INST ROM)
/// 16 bytes RP5H01 PROM CounterOut output (needed to decrypt the INST ROM) (usually constant: 00,00,00,00,FF,FF,FF,FF,00,00,00,00,FF,FF,FF,FF)
/// </remarks>
/// TODO: Split into 2 parts
public byte[] PlayChoicePROM { get; set; } = [];
/// <summary>

15
SabreTools.Serialization/Models/NES/Constants.cs Normal file
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@@ -0,0 +1,15 @@
namespace SabreTools.Data.Models.NES
{
public static class Constants
{
/// <summary>
/// NES<EOF>
/// </summary>
public static readonly byte[] SignatureBytes = [0x4E, 0x45, 0x53, 0x1A];
/// <summary>
/// NES<EOF>
/// </summary>
public static readonly string SignatureString = "NES" + (char)0x1A;
}
}

2
SabreTools.Serialization/Models/NES/Header2.cs
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@@ -70,7 +70,7 @@ namespace SabreTools.Data.Models.NES
/// Number of miscellaneous ROMs present
/// </summary>
/// <remarks>Only bits 0-1 are used</remarks>
public bool MiscellaneousROMs { get; set; }
public byte MiscellaneousROMs { get; set; }
/// <summary>
/// Default Expansion Device

143
SabreTools.Serialization/Readers/NESCart.cs Normal file
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@@ -0,0 +1,143 @@
using System.IO;
using SabreTools.Data.Models.NES;
using SabreTools.IO.Extensions;
using static SabreTools.Data.Models.NES.Constants;
namespace SabreTools.Serialization.Readers
{
public class NESCart : BaseBinaryReader<Cart>
{
/// <inheritdoc/>
public override Cart? Deserialize(Stream? data)
{
// If the data is invalid
if (data is null || !data.CanRead)
return null;
try
{
// Cache the current offset
long initialOffset = data.Position;
// Create a new NES cart image to fill
var cart = new Cart();
#region Header
// Try to parse the header
var header = ParseHeader(data);
if (header == null)
return null;
// Set the header
cart.Header = header;
#endregion
// Read the trainer data, if necessary
#if NET20 || NET35
if ((cart.Header.Flag6 & Flag6.TrainerPresent) != 0)
#else
if (cart.Header.Flag6.HasFlag(Flag6.TrainerPresent))
#endif
cart.Trainer = data.ReadBytes(512);
// Read the PRG-ROM data
// TODO: Make model for PRG-ROM data blocks
int prgRomSize = cart.Header.PRGROMSize * 16384;
if (prgRomSize > 0)
cart.PRGROMData = data.ReadBytes(prgRomSize);
// Read the CHR-ROM data, if necessary
int chrRomSize = cart.Header.CHRROMSize * 8192;
if (chrRomSize > 0)
cart.CHRROMData = data.ReadBytes(chrRomSize);
// Read the PlayChoice INST-ROM and PROM data, if necessary
#if NET20 || NET35
if ((cart.Header.Flag7 & Flag7.PlayChoice10) != 0
&& (cart.Header.Flag7 & Flag7.VSUnisystem) == 0)
#else
if (cart.Header.Flag7.HasFlag(Flag7.PlayChoice10)
&& !cart.Header.Flag7.HasFlag(Flag7.VSUnisystem))
#endif
{
cart.PlayChoiceINSTROM = data.ReadBytes(8192);
cart.PlayChoicePROM = data.ReadBytes(32);
}
// Read the cart title, if it exists
// TODO: Read cart title
return cart;
}
catch
{
// Ignore the actual error
return null;
}
}
/// <summary>
/// Parse a Stream into a Header
/// </summary>
/// <param name="data">Stream to parse</param>
/// <returns>Filled Header on success, null on error</returns>
public static Header? ParseHeader(Stream data)
{
// Cache data until NES 2.0 flag determined
byte[] identificationString = data.ReadBytes(4);
if (identificationString.EqualsExactly(SignatureBytes))
return null;
byte prgRomSize = data.ReadByteValue();
byte chrRomSize = data.ReadByteValue();
Flag6 flag6 = (Flag6)data.ReadByteValue();
Flag7 flag7 = (Flag7)data.ReadByteValue();
// NES 2.0
#if NET20 || NET35
if ((flag7 & Flag7.NES20) != 0)
#else
if (flag7.HasFlag(Flag7.NES20))
#endif
{
var obj = new Header2();
obj.IdentificationString = identificationString;
obj.PRGROMSize = prgRomSize;
obj.CHRROMSize = chrRomSize;
obj.Flag6 = flag6;
obj.Flag7 = flag7;
obj.MapperMSBSubmapper = data.ReadByteValue();
obj.PRGCHRMSB = data.ReadByteValue();
obj.PRGRAMEEPROMSize = data.ReadByteValue();
obj.CHRRAMSize = data.ReadByteValue();
obj.CPUPPUTiming = (CPUPPUTiming)data.ReadByteValue();
obj.ExtendedSystemType = (ExtendedSystemType)data.ReadByteValue();
obj.MiscellaneousROMs = data.ReadByteValue();
obj.DefaultExpansionDevice = (DefaultExpansionDevice)data.ReadByteValue();
return obj;
}
// NES 1.0
else
{
var obj = new Header1();
obj.IdentificationString = identificationString;
obj.PRGROMSize = prgRomSize;
obj.CHRROMSize = chrRomSize;
obj.Flag6 = flag6;
obj.Flag7 = flag7;
obj.PRGRAMSize = data.ReadByteValue();
obj.TVSystem = (TVSystem)data.ReadByteValue();
obj.Flag10 = (Flag10)data.ReadByteValue();
obj.Padding = data.ReadBytes(5);
return obj;
}
}
}
}