114 lines
2.5 KiB
C#
114 lines
2.5 KiB
C#
using BizHawk.Common;
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using BizHawk.Common.NumberExtensions;
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using System;
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namespace BizHawk.Emulation.Cores.Atari.A7800Hawk
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{
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// Super Game mapper but with extra ROM at the start of the file
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// Have to add 1 to bank number to get correct bank value
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public class MapperSGE : MapperBase
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{
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public byte bank = 0;
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public override byte ReadMemory(ushort addr)
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{
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if (addr >= 0x1000 && addr < 0x1800)
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{
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//could be hsbios RAM here
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if (Core._hsbios != null)
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{
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return Core._hsram[addr - 0x1000];
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}
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return 0xFF;
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}
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else if (addr < 0x4000)
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{
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// could be either RAM mirror or ROM
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if (addr >= 0x3000 && Core._hsbios != null)
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{
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return Core._hsbios[addr - 0x3000];
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}
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else
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{
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return Core.RAM[0x800 + addr & 0x7FF];
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}
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}
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else
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{
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// cartridge and other OPSYS
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if (addr >= (0x10000 - Core._bios.Length) && !Core.A7800_control_register.Bit(2))
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{
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return Core._bios[addr - (0x10000 - Core._bios.Length)];
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}
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else
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{
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if (addr >=0xC000)
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{
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// bank 7 is fixed
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return Core._rom[Core._rom.Length - (0x10000 - addr)];
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}
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else if (addr >= 0x8000)
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{
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// return whatever bank is there
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// but remember we need to add 1 to adjust for the extra bank at the beginning
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int temp_addr = addr - 0x8000;
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return Core._rom[temp_addr + (bank + 1) * 0x4000];
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}
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else
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{
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// return the 16k extra ROM (located at beginning of file)
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int temp_addr = addr - 0x4000;
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return Core._rom[temp_addr];
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}
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}
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}
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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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public override void WriteMemory(ushort addr, byte value)
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{
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if (addr >= 0x1000 && addr < 0x1800)
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{
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//could be hsbios RAM here
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if (Core._hsbios != null)
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{
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Core._hsram[addr - 0x1000] = value;
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}
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}
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else if (addr < 0x4000)
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{
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// could be either RAM mirror or ROM
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if (addr >= 0x3000 && Core._hsbios != null)
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{
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}
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else
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{
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Core.RAM[0x800 + addr & 0x7FF] = value;
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}
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}
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else
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{
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// cartridge and other OPSYS
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if (addr>=0x8000)
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{
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bank = (byte)(value & 0x7);
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}
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}
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}
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public override void PokeMemory(ushort addr, byte value)
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{
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WriteMemory(addr, value);
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}
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public override void SyncState(Serializer ser)
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{
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ser.Sync("Bank", ref bank);
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}
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}
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}
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