117 lines
2.9 KiB
C#
117 lines
2.9 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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internal sealed class Mapper227 : NesBoardBase
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{
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private int _prgBankMask16K;
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private int prg;
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private bool _vramProtected;
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private byte[] _prgBanks16K = new byte[2];
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// 1200-in-1
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// [NJXXX] Xiang Shuai Chuan Qi
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public override bool Configure(EDetectionOrigin origin)
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{
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//configure
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switch (Cart.BoardType)
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{
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case "MAPPER227":
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//AssertVram(16);
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Cart.VramSize = 16;
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break;
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default:
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return false;
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}
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_prgBankMask16K = (Cart.PrgSize / 16) - 1;
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SetMirrorType(EMirrorType.Vertical);
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_vramProtected = false;
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_prgBanks16K[0] = _prgBanks16K[1] = 0;
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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(nameof(prg), ref prg);
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ser.Sync(nameof(_prgBanks16K), ref _prgBanks16K, false);
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}
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public override byte ReadPrg(int addr)
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{
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int bank_16k = addr >> 14;
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int ofs = addr & ((1 << 14) - 1);
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bank_16k = _prgBanks16K[bank_16k];
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bank_16k &= _prgBankMask16K;
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addr = (bank_16k << 14) | ofs;
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return Rom[addr];
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}
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public override void WritePrg(int addr, byte value)
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{
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bool S = addr.Bit(0);
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bool M_horz = addr.Bit(1);
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int p = (addr >> 2) & 0x1F;
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p += addr.Bit(8) ? 0x20 : 0;
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bool o = addr.Bit(7);
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bool L = addr.Bit(9);
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//virtuaNES doesnt do this.
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//fceux does it...
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//if we do it, [NJXXX] Xiang Shuai Chuan Qi will not be able to set any patterns
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//maybe only the multicarts do it, to keep the game from clobbering vram on accident
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//vram_protected = o;
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if (o == true && S == false)
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{
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_prgBanks16K[0] = (byte)(p);
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_prgBanks16K[1] = (byte)(p);
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}
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if (o == true && S == true)
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{
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_prgBanks16K[0] = (byte)((p & ~1));
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_prgBanks16K[1] = (byte)((p & ~1) + 1);
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}
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if (o == false && S == false && L == false)
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{
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_prgBanks16K[0] = (byte)p;
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_prgBanks16K[1] = (byte)(p & 0x38);
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}
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if (o == false && S == true && L == false)
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{
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_prgBanks16K[0] = (byte)(p & 0x3E);
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_prgBanks16K[1] = (byte)(p & 0x38);
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}
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if (o == false && S == false && L == true)
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{
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_prgBanks16K[0] = (byte)p;
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_prgBanks16K[1] = (byte)(p | 0x07);
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}
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if (o == false && S == true && L == true)
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{
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_prgBanks16K[0] = (byte)(p & 0x3E);
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_prgBanks16K[1] = (byte)(p | 0x07);
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}
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_prgBanks16K[0] = (byte)(_prgBanks16K[0]&_prgBankMask16K);
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_prgBanks16K[1] = (byte)(_prgBanks16K[1]&_prgBankMask16K);
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if (M_horz) SetMirrorType(EMirrorType.Horizontal);
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else SetMirrorType(EMirrorType.Vertical);
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}
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public override void WritePpu(int addr, byte value)
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{
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if (addr < 0x2000)
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{
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if (_vramProtected)
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return;
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else base.WritePpu(addr, value);
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}
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else base.WritePpu(addr, value);
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}
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}
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}
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