86 lines
1.7 KiB
C#
86 lines
1.7 KiB
C#
using BizHawk.Common;
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namespace BizHawk.Emulation.Cores.Atari.Atari2600
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{
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/*
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This was used by Commavid. It allowed for both ROM and RAM on the cartridge,
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without using bankswitching. There's 2K of ROM and 1K of RAM.
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2K of ROM is mapped at 1800-1FFF.
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1K of RAM is mapped in at 1000-17FF.
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The read port is at 1000-13FF.
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The write port is at 1400-17FF.
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Example games:
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Magicard
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*/
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internal class mCV : MapperBase
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{
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private byte[] _ram = new byte[1024];
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public override bool HasCartRam => true;
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public override byte[] CartRam => _ram;
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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("aux_ram", ref _ram, false);
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}
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public override void HardReset()
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{
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_ram = new byte[1024];
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base.HardReset();
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}
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public override byte ReadMemory(ushort addr)
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{
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if (addr < 0x1000)
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{
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return base.ReadMemory(addr);
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}
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if (addr < 0x1400)
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{
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return _ram[(addr & 0x3FF)];
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}
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if (addr >= 0x1800 && addr < 0x2000)
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{
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return Core.Rom[(addr & 0x7FF)];
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}
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return base.ReadMemory(addr);
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}
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public override byte PeekMemory(ushort addr)
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{
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return ReadMemory(addr);
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}
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private void WriteMem(ushort addr, byte value, bool poke)
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{
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if (addr < 0x1000)
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{
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base.WriteMemory(addr, value);
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}
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else if (addr >= 0x1400 && addr < 0x1800)
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{
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_ram[(addr & 0x3FF)] = value;
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}
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}
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public override void WriteMemory(ushort addr, byte value)
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{
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WriteMem(addr, value, poke: false);
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}
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public override void PokeMemory(ushort addr, byte value)
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{
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WriteMem(addr, value, poke: true);
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}
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}
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}
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