/*********************************************************************\

*This file is part of My Nes                                          *

*A Nintendo Entertainment System Emulator.                            *

*                                                                     *

*Copyright © Ala Hadid 2009 - 2011                                    *

*E-mail: mailto:ahdsoftwares@hotmail.com                              *

*                                                                     *

*My Nes is free software: you can redistribute it and/or modify       *

*it under the terms of the GNU General Public License as published by *

*the Free Software Foundation, either version 3 of the License, or    *

*(at your option) any later version.                                  *

*                                                                     *

*My Nes is distributed in the hope that it will be useful,            *

*but WITHOUT ANY WARRANTY; without even the implied warranty of       *

*MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the        *

*GNU General Public License for more details.                         *

*                                                                     *

*You should have received a copy of the GNU General Public License    *

*along with this program.  If not, see <http://www.gnu.org/licenses/>.*

\*********************************************************************/

namespace MyNes.Nes

{

    class Mapper255 : Mapper

    {

        byte Mapper225_reg0 = 0x0F;

        byte Mapper225_reg1 = 0x0F;

        byte Mapper225_reg2 = 0x0F;

        byte Mapper225_reg3 = 0x0F;



        public Mapper255(NesSystem nesSystem)

            : base(nesSystem) { }



        public override void Poke(int address, byte data)

        {

            if ((address >= 0x8000) && (address <= 0xFFFF))

            {

                int banks = ((address & 0x4000) != 0) ? 1 : 0;

                ushort wher = (ushort)((address & 0x0Fc0) >> 7);

                cpuMemory.Switch8kChrRom(((address & 0x003F) + (banks << 6)) * 8);

                if ((address & 0x1000) != 0)//A12

                {

                    if ((address & 0x0040) != 0)//A6

                    {

                        cpuMemory.Switch16kPrgRom((((wher + (banks << 5)) << 1) + 1) * 4, 0);

                        cpuMemory.Switch16kPrgRom((((wher + (banks << 5)) << 1) + 1) * 4, 1);

                    }

                    else

                    {

                        cpuMemory.Switch16kPrgRom(((wher + (banks << 5)) << 1) * 4, 0);

                        cpuMemory.Switch16kPrgRom(((wher + (banks << 5)) << 1) * 4, 1);

                    }

                }

                else

                {

                    cpuMemory.Switch32kPrgRom((wher + (banks << 5)) * 8);//ignore A6

                }

                cartridge.Mirroring = ((address >> 13) & 1) == 0 ? Mirroring.ModeVert : Mirroring.ModeHorz;

            }

            else if ((address >= 0x5800) && (address <= 0x5FFF))

            {

                switch (address & 0x3)

                {

                    case 0: Mapper225_reg0 = (byte)(data & 0xf); break;

                    case 1: Mapper225_reg1 = (byte)(data & 0xf); break;

                    case 2: Mapper225_reg2 = (byte)(data & 0xf); break;

                    case 3: Mapper225_reg3 = (byte)(data & 0xf); break;

                }

            }

        }

        protected override void Initialize(bool initializing)

        {

            cpuMemory.Map(0x4018, 0x7FFF, Peek, Poke);

            cpuMemory.Switch32kPrgRom(0);

            if (cartridge.HasCharRam)

                cpuMemory.FillChr(8);

            cpuMemory.Switch8kChrRom(0);

            Mapper225_reg0 = 0xF;

            Mapper225_reg1 = 0xF;

            Mapper225_reg2 = 0xF;

            Mapper225_reg3 = 0xF;

        }

        public override byte Peek(int addr)

        {

            if ((addr >= 0x5800) && (addr <= 0x5FFF))

            {

                switch (addr & 0x3)

                {

                    case 0: return Mapper225_reg0;

                    case 1: return Mapper225_reg1;

                    case 2: return Mapper225_reg2;

                    case 3: return Mapper225_reg3;

                }

            }

            return 0xF;

        }

    }

}