74 lines
1.5 KiB
C#
74 lines
1.5 KiB
C#
using BizHawk.Common;
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using BizHawk.Common.NumberExtensions;
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// https://wiki.nesdev.com/w/index.php/INES_Mapper_200
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namespace BizHawk.Emulation.Cores.Nintendo.NES
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{
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internal sealed class Mapper200 : NesBoardBase
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{
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int prg_reg_16k, chr_reg_8k;
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int prg_bank_mask_16k;
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int chr_bank_mask_8k;
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public override bool Configure(EDetectionOrigin origin)
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{
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switch (Cart.BoardType)
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{
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case "MAPPER200":
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case "MAPPER229":
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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_16k = Cart.PrgSize / 16 - 1;
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chr_bank_mask_8k = Cart.ChrSize / 8 - 1;
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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(nameof(prg_reg_16k), ref prg_reg_16k);
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ser.Sync(nameof(chr_reg_8k), ref chr_reg_8k);
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base.SyncState(ser);
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}
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public override void WritePrg(int addr, byte value)
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{
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if (addr.Bit(3))
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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 reg = addr & 0x07;
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prg_reg_16k = reg & prg_bank_mask_16k;
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chr_reg_8k = reg & chr_bank_mask_8k;
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}
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public override byte ReadPrg(int addr)
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{
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if (addr < 0x4000)
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{
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return Rom[(prg_reg_16k * 0x4000) + addr];
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}
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else
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{
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return Rom[(prg_reg_16k * 0x4000) + addr - 0x4000];
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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_8k * 0x2000) + addr];
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}
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return base.ReadPpu(addr);
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}
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}
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}
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