64 lines
1.3 KiB
C#
64 lines
1.3 KiB
C#
using BizHawk.Common;
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using BizHawk.Common.NumberExtensions;
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// http://wiki.nesdev.com/w/index.php/INES_Mapper_061
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namespace BizHawk.Emulation.Cores.Nintendo.NES
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{
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internal sealed class Mapper61 : NesBoardBase
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{
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public int prg_page;
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public bool prg_mode;
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public int prg_byte_mask;
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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 "MAPPER061":
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break;
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default:
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return false;
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}
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SetMirrorType(EMirrorType.Vertical);
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prg_page = 0;
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prg_mode = false;
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prg_byte_mask = Cart.PrgSize * 1024 - 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_page), ref prg_page);
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ser.Sync(nameof(prg_mode), ref prg_mode);
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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(7))
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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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prg_mode = addr.Bit(4);
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prg_page = ((addr & 0x0F) << 1) | ((addr & 0x20) >> 5);
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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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return Rom[(((prg_page >> 1) * 0x8000) + addr) & prg_byte_mask];
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}
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else
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{
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return Rom[((prg_page * 0x4000) + (addr & 0x03FFF)) & prg_byte_mask];
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}
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}
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}
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}
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