72 lines
1.3 KiB
C#
72 lines
1.3 KiB
C#
using BizHawk.Common;
|
|
|
|
namespace BizHawk.Emulation.Cores.Atari.Atari2600
|
|
{
|
|
/*
|
|
Cartridge class used for SB "SUPERbanking" 128k-256k bankswitched games.
|
|
There are either 32 or 64 4K banks.
|
|
*/
|
|
internal class mSB : MapperBase
|
|
{
|
|
private int _bank4K;
|
|
private int myStartBank
|
|
{
|
|
get { return (Core.Rom.Length >> 12) - 1; }
|
|
}
|
|
public override void SyncState(Serializer ser)
|
|
{
|
|
base.SyncState(ser);
|
|
ser.Sync("bank_4k", ref _bank4K);
|
|
}
|
|
|
|
public override void HardReset()
|
|
{
|
|
_bank4K = 0;
|
|
base.HardReset();
|
|
}
|
|
|
|
private byte ReadMem(ushort addr, bool peek)
|
|
{
|
|
if (!peek)
|
|
{
|
|
Address(addr);
|
|
}
|
|
|
|
if (addr < 0x1000)
|
|
{
|
|
return base.ReadMemory(addr);
|
|
}
|
|
|
|
return Core.Rom[(_bank4K << 12) + (addr & 0xFFF)];
|
|
}
|
|
|
|
public override byte ReadMemory(ushort addr)
|
|
{
|
|
return ReadMem(addr, false);
|
|
}
|
|
|
|
public override byte PeekMemory(ushort addr)
|
|
{
|
|
return ReadMem(addr, true);
|
|
}
|
|
|
|
public override void WriteMemory(ushort addr, byte value)
|
|
{
|
|
Address(addr);
|
|
if (addr < 0x1000)
|
|
{
|
|
base.WriteMemory(addr, value);
|
|
}
|
|
}
|
|
|
|
private void Address(ushort addr)
|
|
{
|
|
var temp = addr & (0x17FF + (Core.Rom.Length >> 12));
|
|
if ((temp & 0x1800) == 0x800)
|
|
{
|
|
_bank4K = temp & myStartBank;
|
|
}
|
|
}
|
|
}
|
|
}
|