138 lines
2.2 KiB
C#
138 lines
2.2 KiB
C#
using BizHawk.Common;
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namespace BizHawk.Emulation.Cores.Nintendo.NES
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{
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internal sealed class Mapper043 : NesBoardBase
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{
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int prg = 0;
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int irqcnt = 0;
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bool irqenable = false;
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bool swap;
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private static int[] lut = { 4, 3, 5, 3, 6, 3, 7, 3 };
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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 "MAPPER043":
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break;
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default:
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return false;
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}
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Cart.WramSize = 0;
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// not sure on initial mirroring
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SetMirrorType(EMirrorType.Vertical);
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return true;
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}
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public override void WriteExp(int addr, byte value)
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{
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addr += 0x4000;
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switch (addr & 0xF1FF)
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{
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case 0x4022:
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prg = lut[value & 0x7];
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break;
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case 0x4120:
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swap = (value & 1) == 1;
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break;
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case 0x4122:
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irqenable = (value & 1) == 1;
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IrqSignal = false;
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irqcnt = 0;
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break;
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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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addr += 0x8000;
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switch (addr & 0xF1FF)
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{
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case 0x8122:
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irqenable = (value & 1) == 1;
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IrqSignal = false;
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irqcnt = 0;
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break;
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}
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}
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public override byte ReadExp(int addr)
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{
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if (addr > 0x1000)
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{
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return Rom[(addr - 0x1000) + 8 * 0x2000];
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}
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else return base.ReadExp(addr);
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}
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public override byte ReadWram(int addr)
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{
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if (swap)
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{
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return Rom[addr];
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}
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else
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{
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return Rom[addr + 0x4000];
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}
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}
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public override byte ReadPrg(int addr)
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{
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if (addr < 0x2000)
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{
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return Rom[addr + 0x2000];
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}
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else if (addr < 0x4000)
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{
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return Rom[addr - 0x2000];
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}
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else if (addr < 0x6000)
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{
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return Rom[(addr - 0x4000) + prg * 0x2000];
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}
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else
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{
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if (swap)
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{
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return Rom[(addr - 0x6000) + 8 * 0x2000];
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}
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else
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{
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return Rom[(addr - 0x6000) + 9 * 0x2000];
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}
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}
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}
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public override void ClockCpu()
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{
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if (irqenable)
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{
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irqcnt++;
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if (irqcnt >= 4096)
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{
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irqenable = false;
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IrqSignal = true;
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}
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}
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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(irqenable), ref irqenable);
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ser.Sync(nameof(irqcnt), ref irqcnt);
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ser.Sync(nameof(swap), ref swap);
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}
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}
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}
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