88 lines
1.6 KiB
C#
88 lines
1.6 KiB
C#
using BizHawk.Common;
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namespace BizHawk.Emulation.Cores.Nintendo.NES
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{
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public sealed class Mapper235 : NES.NESBoardBase
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{
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private int _reg;
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private int _prg16BankMask;
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private int _prg32BankMask;
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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 "MAPPER235":
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break;
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default:
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return false;
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}
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_prg16BankMask = Cart.prg_size / 16 - 1;
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_prg32BankMask = Cart.prg_size / 32 - 1;
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SetMirrorType(Cart.pad_h, Cart.pad_v);
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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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base.SyncState(ser);
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ser.Sync("reg", ref _reg);
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}
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public override byte ReadPRG(int addr)
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{
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if ((_reg & 0x800) > 0)
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{
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int bank;
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if (addr < 0x4000)
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{
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bank = ((_reg & 0x300) >> 3) | ((_reg & 0x1F) << 1) | ((_reg >> 12) & 1);
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}
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else
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{
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bank = ((_reg & 0x300) >> 3) | ((_reg & 0x1F) << 1) | ((_reg >> 12) & 1);
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}
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return ROM[((bank & _prg16BankMask) * 0x4000) + (addr & 0x3FFF)];
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}
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else
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{
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int bank = ((_reg & 0x300) >> 4) | (_reg & 0x1F);
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return ROM[((bank & _prg32BankMask) * 0x8000) + (addr & 0x7FFF)];
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}
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}
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public override void WritePRG(int addr, byte value)
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{
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_reg = addr;
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SyncMirroring();
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}
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private void SyncMirroring()
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{
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if ((_reg & 0x400) > 0)
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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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int type = ((_reg >> 13) & 1) ^ 1;
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if (type == 0)
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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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}
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}
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}
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}
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