103 lines
2.1 KiB
C#
103 lines
2.1 KiB
C#
using BizHawk.Common;
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// http://wiki.nesdev.com/w/index.php/INES_Mapper_246
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namespace BizHawk.Emulation.Cores.Nintendo.NES
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{
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public sealed class Mapper246 : NES.NESBoardBase
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{
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int prg_bank_mask_8k;
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byte[] prg_banks_8k = new byte[4];
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int chr_bank_mask_2k;
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byte[] chr_banks_2k = new byte[4];
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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 "MAPPER246":
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break;
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default:
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return false;
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}
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prg_bank_mask_8k = (Cart.prg_size / 8) - 1;
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chr_bank_mask_2k = (Cart.chr_size / 2) - 1;
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prg_banks_8k[3] = 0xFF;
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SetMirrorType(EMirrorType.Horizontal);
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SyncMap();
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return true;
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}
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private void SyncMap()
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{
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ApplyMemoryMapMask(prg_bank_mask_8k, prg_banks_8k);
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ApplyMemoryMapMask(chr_bank_mask_2k, chr_banks_2k);
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}
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public override void SyncState(Serializer ser)
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{
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base.SyncState(ser);
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ser.Sync(nameof(prg_banks_8k), ref prg_banks_8k, false);
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ser.Sync(nameof(chr_banks_2k), ref chr_banks_2k, false);
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}
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public override void WriteWRAM(int addr, byte value)
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{
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if (addr < 0x0800)
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{
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addr &= 0x0007;
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switch (addr)
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{
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case 0:
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prg_banks_8k[0] = value;
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break;
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case 1:
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prg_banks_8k[1] = value;
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break;
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case 2:
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prg_banks_8k[2] = value;
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break;
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case 3:
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prg_banks_8k[3] = value;
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break;
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case 4:
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chr_banks_2k[0] = value;
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break;
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case 5:
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chr_banks_2k[1] = value;
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break;
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case 6:
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chr_banks_2k[2] = value;
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break;
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case 7:
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chr_banks_2k[3] = value;
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break;
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}
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SyncMap();
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}
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else
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{
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base.WriteWRAM(addr, value);
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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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addr = ApplyMemoryMap(11, chr_banks_2k, addr);
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return base.ReadPPUChr(addr);
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}
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return base.ReadPPU(addr);
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}
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public override byte ReadPRG(int addr)
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{
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addr = ApplyMemoryMap(13, prg_banks_8k, addr);
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return ROM[addr];
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}
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}
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}
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