Mapper000B.cs

using System;
using System.Collections.Generic;

namespace BizHawk.Emulation.Cores.Computers.Commodore64.Cartridge
{
    // Westermann Learning mapper.
    // Starts up with both banks enabled, any read to DFxx
    // turns off the high bank by bringing GAME high.
    // I suspect that the game loads by copying all hirom to
    // the RAM underneath (BASIC variable values probably)
    // and then disables once loaded.

    public abstract partial class CartridgeDevice
    {
        private sealed class Mapper000B : CartridgeDevice
        {
            [SaveState.DoNotSave]
            private readonly int[] _rom = new int[0x4000];

            public Mapper000B(IList<int> newAddresses, IList<int[]> newData)
            {
                validCartridge = false;

                for (var i = 0; i < 0x4000; i++)
                    _rom[i] = 0xFF;

                if (newAddresses[0] != 0x8000)
                {
                    return;
                }

                Array.Copy(newData[0], _rom, Math.Min(newData[0].Length, 0x4000));
                validCartridge = true;
            }

            public override int Peek8000(int addr)
            {
                return _rom[addr];
            }

            public override int PeekA000(int addr)
            {
                return _rom[addr | 0x2000];
            }

            public override int Read8000(int addr)
            {
                return _rom[addr];
            }

            public override int ReadA000(int addr)
            {
                return _rom[addr | 0x2000];
            }

            public override int ReadDF00(int addr)
            {
                pinGame = true;
                return base.ReadDF00(addr);
            }
        }
    }

}