116 lines
2.2 KiB
C#
116 lines
2.2 KiB
C#
using System;
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using BizHawk.Common;
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namespace BizHawk.Emulation.Cores.Nintendo.NES
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{
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// pirate FDS conversion
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// this is probably two different boards, but they seem to work well enough the same
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internal sealed class Mapper042 : NesBoardBase
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{
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int prg = 0;
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int chr = 0;
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int irqcnt = 0;
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bool irqenable = false;
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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 "MAPPER042":
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break;
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default:
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return false;
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}
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AssertPrg(128);
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if (Cart.VramSize == 0)
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AssertChr(128);
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else
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{
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AssertVram(8);
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AssertChr(0);
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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 WritePrg(int addr, byte value)
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{
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addr &= 0x6003;
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switch (addr)
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{
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case 0x0000:
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chr = value & 15;
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break;
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case 0x6000:
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prg = value & 15;
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break;
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case 0x6001:
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if ((value & 8) != 0)
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SetMirrorType(EMirrorType.Horizontal);
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else
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SetMirrorType(EMirrorType.Vertical);
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break;
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case 0x6002:
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Console.WriteLine("{0:x4}:{1:x2} @{2}", addr + 0x8000, value, NES.ppu.ppur.status.sl);
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if ((value & 2) == 0)
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{
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irqcnt = 0;
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irqenable = false;
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IrqSignal = false;
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}
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else
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irqenable = true;
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break;
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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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return Rom[addr | 0x18000];
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}
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public override byte ReadWram(int addr)
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{
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return Rom[addr | prg << 13];
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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 >= 32768)
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irqcnt -= 32768;
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IrqSignal = irqcnt >= 24576;
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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(chr), ref chr);
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ser.Sync(nameof(irqenable), ref irqenable);
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ser.Sync(nameof(irqcnt), ref irqcnt);
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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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if (Vram != null)
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return Vram[addr];
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else
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return Vrom[addr | chr << 13];
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}
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else
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return base.ReadPpu(addr);
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}
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}
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}
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