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Atari - implement UA mapper (untested)

This commit is contained in:
andres.delikat 2012-04-02 16:58:04 +00:00
parent aed58c67e4
commit 5d28f8727a
1 changed files with 34 additions and 0 deletions
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34
BizHawk.Emulation/Consoles/Atari/2600/Mappers/mUA.cs
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@ -5,8 +5,42 @@ using System.Text;
namespace BizHawk.Emulation.Consoles.Atari._2600
{
/*
UA (UA Ltd)
-----
This one was found out later on, lurking on a proto of Pleaides. It works with 8K of ROM
and banks it in 4K at a time.
Accessing 0220 will select the first bank, and accessing 0240 will select the second.
*/
class mUA : MapperBase
{
int toggle = 0;
public override byte ReadMemory(ushort addr)
{
Address(addr);
if (addr < 0x1000) return base.ReadMemory(addr);
return core.rom[toggle * 4 * 1024 + (addr & 0xFFF)];
}
public override void WriteMemory(ushort addr, byte value)
{
Address(addr);
if (addr < 0x1000) base.WriteMemory(addr, value);
}
public override void SyncState(Serializer ser)
{
base.SyncState(ser);
ser.Sync("toggle", ref toggle);
}
void Address(ushort addr)
{
if (addr == 0x0220) toggle = 0;
else if (addr == 0x0240) toggle = 1;
}
}
}