67 lines
2.0 KiB
C#
67 lines
2.0 KiB
C#
using System;
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namespace AxibugEmuOnline.Client.UNES
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{
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public class Cartridge
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{
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public readonly byte[] Raw;
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public readonly int PRGROMSize;
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public readonly int CHRROMSize;
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public readonly int PRGRAMSize;
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public readonly int PRGROMOffset;
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public readonly int MapperNumber;
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public readonly byte[] PRGROM;
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public readonly byte[] CHRROM;
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public VRAMMirroringMode MirroringMode;
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public enum VRAMMirroringMode
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{
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Horizontal, Vertical, All, Upper, Lower
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}
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public Cartridge(byte[] bytes)
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{
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Raw = bytes;
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var header = BitConverter.ToInt32(Raw, 0);
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if (header != 0x1A53454E) // "NES<EOF>"
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{
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throw new FormatException("unexpected header value " + header.ToString("X"));
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}
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PRGROMSize = Raw[4] * 0x4000; // 16kb units
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CHRROMSize = Raw[5] * 0x2000; // 8kb units
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PRGRAMSize = Raw[8] * 0x2000;
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var hasTrainer = (Raw[6] & 0b100) > 0;
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PRGROMOffset = 16 + (hasTrainer ? 512 : 0);
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MirroringMode = (Raw[6] & 0x1) > 0 ? VRAMMirroringMode.Vertical : VRAMMirroringMode.Horizontal;
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if ((Raw[6] & 0x8) > 0)
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{
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MirroringMode = VRAMMirroringMode.All;
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}
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MapperNumber = (Raw[6] >> 4) | (Raw[7] & 0xF0);
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PRGROM = new byte[PRGROMSize];
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Array.Copy(Raw, PRGROMOffset, PRGROM, 0, PRGROMSize);
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if (CHRROMSize == 0)
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{
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CHRROM = new byte[0x2000];
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}
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else
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{
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CHRROM = new byte[CHRROMSize];
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Array.Copy(Raw, PRGROMOffset + PRGROMSize, CHRROM, 0, CHRROMSize);
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}
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}
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public override string ToString()
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{
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return $"Cartridge{{PRGROMSize={PRGROMSize}, CHRROMSize={CHRROMSize}, PRGROMOffset={PRGROMOffset}, MapperNumber={MapperNumber}}}";
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}
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}
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}
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