Mapper0001.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace BizHawk.Emulation.Cores.Computers.Commodore64.Cartridge
{
    public abstract partial class CartridgeDevice
    {
        private sealed class Mapper0001 : CartridgeDevice
        {
            [SaveState.SaveWithName("RAM")] private readonly int[] _ram = new int[0x2000];
            [SaveState.SaveWithName("RAMEnabled")] private bool _ramEnabled;
            [SaveState.DoNotSave] private readonly int[] _rom = new int[0x8000];
            [SaveState.SaveWithName("ROMOffset")] private int _romOffset;
            [SaveState.SaveWithName("CartEnabled")] private bool _cartEnabled;

            public Mapper0001(IList<int> newAddresses, IList<int> newBanks, IList<int[]> newData)
            {
                pinExRom = false;
                pinGame = false;
                for (var i = 0; i < newData.Count; i++)
                {
                    if (newAddresses[i] == 0x8000)
                        Array.Copy(newData[i], 0, _rom, 0x2000 * newBanks[i], 0x2000);
                }
                _romOffset = 0;
                _cartEnabled = true;
            }

            public override void HardReset()
            {
                base.HardReset();
                pinExRom = false;
                pinGame = false;
                for (var i = 0; i < 0x2000; i++)
                    _ram[i] = 0x00;
                _romOffset = 0;
                _cartEnabled = true;
            }

            public override int Peek8000(int addr)
            {
                return GetLoRom(addr);
            }

            public override int PeekA000(int addr)
            {
                return Peek8000(addr);
            }

            public override int PeekDF00(int addr)
            {
                return GetIo2(addr);
            }

            public override void Poke8000(int addr, int val)
            {
                SetLoRom(addr, val);
            }

            public override void PokeA000(int addr, int val)
            {
                Poke8000(addr, val);
            }

            public override void PokeDE00(int addr, int val)
            {
                SetState(val);
            }

            public override void PokeDF00(int addr, int val)
            {
                SetIo2(addr, val);
            }

            public override int Read8000(int addr)
            {
                return GetLoRom(addr);
            }

            public override int ReadA000(int addr)
            {
                return GetHiRom(addr);
            }

            public override int ReadDF00(int addr)
            {
                return GetIo2(addr);
            }

            public override void Write8000(int addr, int val)
            {
                SetLoRom(addr, val);
            }

            public override void WriteA000(int addr, int val)
            {
                SetLoRom(addr, val);
            }

            public override void WriteDE00(int addr, int val)
            {
                SetState(val);
            }

            public override void WriteDF00(int addr, int val)
            {
                SetIo2(addr, val);
            }

            private void SetState(int val)
            {
                pinGame = (val & 0x01) == 0;
                pinExRom = (val & 0x02) != 0;
                _cartEnabled = (val & 0x04) == 0;
                _romOffset = (val & 0x18) << 10;
                _ramEnabled = (val & 0x20) == 0;
            }

            private int GetLoRom(int addr)
            {
                return _ramEnabled
                    ? _ram[addr & 0x1FFF]
                    : _rom[(addr & 0x1FFF) | _romOffset];
            }

            private int GetHiRom(int addr)
            {
                return _rom[(addr & 0x1FFF) | _romOffset];
            }

            private void SetLoRom(int addr, int val)
            {
                _ram[addr & 0x1FFF] = val;
            }

            private int GetIo2(int addr)
            {
                if (!_cartEnabled)
                    return ReadOpenBus();

                return _ramEnabled
                    ? _ram[(addr & 0xFF) | 0x1F00]
                    : _rom[(addr & 0xFF) | _romOffset | 0x1F00];
            }

            private void SetIo2(int addr, int val)
            {
                _ram[addr & 0x1FFF] = val & 0xFF;
            }
        }
    }
}