109 lines
1.8 KiB
C#
109 lines
1.8 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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public sealed class Mapper175 : NES.NESBoardBase
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{
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private bool delay;
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private int reg;
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private bool mirr;
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private int chrReg;
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private int prgReg8;
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private int prgRegC;
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private int prgRegE;
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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 "MAPPER175":
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break;
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default:
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return false;
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}
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Sync();
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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("delay", ref delay);
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ser.Sync("reg", ref reg);
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ser.Sync("mirr", ref mirr);
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ser.Sync("chrReg", ref chrReg);
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ser.Sync("prgReg8", ref prgReg8);
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ser.Sync("prgRegC", ref prgRegC);
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ser.Sync("prgRegE", ref prgRegE);
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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 == 0)
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{
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mirr = value.Bit(2);
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delay = true;
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Sync();
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}
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else if (addr == 0x2000)
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{
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reg = value & 0x0F;
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delay = true;
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Sync();
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}
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}
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private void Sync()
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{
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SetMirrorType(mirr ? EMirrorType.Horizontal : EMirrorType.Vertical);
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chrReg = reg;
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prgRegE = (reg << 1) + 1;
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if (!delay)
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{
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prgReg8 = reg;
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prgRegC = reg << 1;
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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[(chrReg << 13) + 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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if (addr == 0x7FFC)
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{
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delay = false;
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Sync();
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}
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if (addr < 0x4000)
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{
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return ROM[(prgReg8 << 14) + (addr & 0x3FFF)];
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}
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else if (addr < 0x6000)
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{
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return ROM[(prgRegC << 13) + (addr & 0x1FFF)];
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}
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else
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{
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return ROM[(prgRegE << 13) + (addr & 0x1FFF)];
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}
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}
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}
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}
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