93 lines
2.8 KiB
C#
93 lines
2.8 KiB
C#
using System;
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namespace VirtualNes.Core
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{
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public abstract class Mapper
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{
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protected NES nes;
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public Mapper(NES parent)
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{
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nes = parent;
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}
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public virtual void Dispose() { }
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public abstract void Reset();
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// $8000-$FFFF Memory write
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public virtual void Write(ushort addr, byte data) { }
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// $8000-$FFFF Memory read(Dummy)
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public virtual void Read(ushort addr, byte data) { }
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// $4100-$7FFF Lower Memory read/write
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public virtual byte ReadLow(ushort addr)
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{
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// $6000-$7FFF WRAM
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if (addr >= 0x6000 && addr <= 0x7FFF)
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{
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return MMU.CPU_MEM_BANK[addr >> 13][addr & 0x1FFF];
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}
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return (byte)(addr >> 8);
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}
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public virtual void WriteLow(ushort addr, byte data)
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{
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if (addr >= 0x6000 && addr <= 0x7FFF)
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{
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MMU.CPU_MEM_BANK[addr >> 13][addr & 0x1FFF] = data;
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}
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}
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// $4018-$40FF Extention register read/write
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public virtual byte ExRead(ushort addr) { return 0x00; }
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public virtual void ExWrite(ushort addr, byte data) { }
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public virtual byte ExCmdRead(EXCMDRD cmd) { return 0x00; }
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public virtual void ExCmdWrite(EXCMDWR cmd, byte data) { }
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// H sync/V sync/Clock sync
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public virtual void HSync(int scanline) { }
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public virtual void VSync() { }
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public virtual void Clock(int cycles) { }
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// PPU address bus latch
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public virtual void PPU_Latch(ushort addr) { }
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// PPU Character latch
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public virtual void PPU_ChrLatch(ushort addr) { }
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// PPU Extension character/palette
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public virtual void PPU_ExtLatchX(int x) { }
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public virtual void PPU_ExtLatch(ushort addr, ref byte chr_l, ref byte chr_h, ref byte attr) { }
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// For State save
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public virtual bool IsStateSave() { return false; }
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public virtual void SaveState(byte[] p) { }
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public virtual void LoadState(byte[] p) { }
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// Extension commands
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// For ExCmdRead command
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public enum EXCMDRD
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{
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EXCMDRD_NONE = 0,
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EXCMDRD_DISKACCESS,
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}
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// For ExCmdWrite command
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public enum EXCMDWR
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{
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EXCMDWR_NONE = 0,
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EXCMDWR_DISKINSERT,
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EXCMDWR_DISKEJECT,
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}
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public static Mapper CreateMapper(NES parent, int no)
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{
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//todo : 实现加载mapper
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switch (no)
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{
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case 4:
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return new Mapper004(parent);
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default:
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throw new NotImplementedException($"Mapper#{no:000} is not Impl");
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}
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}
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}
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}
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