110 lines
2.3 KiB
C#
110 lines
2.3 KiB
C#
using BizHawk.Common;
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using BizHawk.Common.NumberExtensions;
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namespace BizHawk.Emulation.Cores.Nintendo.NES
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{
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// http://wiki.nesdev.com/w/index.php/INES_Mapper_225
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public sealed class Mapper225 : NES.NESBoardBase
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{
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bool prg_mode = false;
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int chr_reg;
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int prg_reg;
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ByteBuffer eRAM = new ByteBuffer(4);
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int chr_bank_mask_8k, prg_bank_mask_16k, prg_bank_mask_32k;
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public override bool Configure(NES.EDetectionOrigin origin)
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{
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switch (Cart.board_type)
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{
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case "MAPPER225":
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case "MAPPER255": // Duplicate of 225 accoring to: http://problemkaputt.de/everynes.htm
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break;
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default:
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return false;
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}
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chr_bank_mask_8k = Cart.chr_size / 8 - 1;
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prg_bank_mask_16k = Cart.prg_size / 16 - 1;
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prg_bank_mask_32k = Cart.prg_size / 32 - 1;
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SetMirrorType(EMirrorType.Vertical);
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return true;
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}
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public override void SyncState(Serializer ser)
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{
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ser.Sync("prg_reg", ref prg_reg);
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ser.Sync("chr_reg", ref chr_reg);
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ser.Sync("prg_mode", ref prg_mode);
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ser.Sync("eRAM", ref eRAM);
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base.SyncState(ser);
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}
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public override void Dispose()
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{
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eRAM.Dispose();
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base.Dispose();
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}
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public override void WritePRG(int addr, byte value)
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{
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addr += 0x8000;
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prg_mode = addr.Bit(12);
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if (addr.Bit(13))
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{
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SetMirrorType(EMirrorType.Horizontal);
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}
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else
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{
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SetMirrorType(EMirrorType.Vertical);
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}
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int high = (addr & 0x4000) >> 8;
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prg_reg = (addr >> 6) & 0x3F | high;
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chr_reg = addr & 0x3F | high;
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}
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public override byte ReadPRG(int addr)
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{
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if (prg_mode == false)
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{
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int bank = (prg_reg >> 1) & prg_bank_mask_32k;
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return ROM[(bank * 0x8000) + addr];
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}
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else
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{
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return ROM[((prg_reg & prg_bank_mask_16k) * 0x4000) + (addr & 0x3FFF)];
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}
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}
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public override byte ReadPPU(int addr)
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{
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if (addr < 0x2000)
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{
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return VROM[((chr_reg & chr_bank_mask_8k) * 0x2000) + addr];
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}
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return base.ReadPPU(addr);
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}
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public override void WriteEXP(int addr, byte value)
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{
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if (addr >= 0x1800)
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{
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eRAM[(addr & 0x03)] = (byte)(value & 0x0F);
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}
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}
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public override byte ReadEXP(int addr)
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{
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if (addr >= 0x1800)
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{
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return eRAM[(addr & 0x03)];
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}
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else
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{
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return base.ReadEXP(addr);
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}
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}
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}
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}
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