AxibugEmuOnline/Core/VirtualNes.Core/Mapper/Mapper043.cs

//////////////////////////////////////////////////////////////////////////
// Mapper043  SMB2J                                                     //
//////////////////////////////////////////////////////////////////////////
using System;
using static VirtualNes.Core.CPU;
using static VirtualNes.MMU;
using BYTE = System.Byte;
using INT = System.Int32;


namespace VirtualNes.Core
{
    public class Mapper043 : Mapper
    {
        BYTE irq_enable;
        INT irq_counter;
        public Mapper043(NES parent) : base(parent)
        {
        }


        public override void Reset()
        {
            irq_enable = 0xFF;
            irq_counter = 0;

            SetPROM_8K_Bank(3, 2);
            SetPROM_32K_Bank(1, 0, 4, 9);

            if (VROM_1K_SIZE != 0)
            {
                SetVROM_8K_Bank(0);
            }
        }

        //BYTE Mapper043::ReadLow(WORD addr)
        public override byte ReadLow(ushort addr)
        {
            if (0x5000 <= addr && addr < 0x6000)
            {
                byte[] pPtr = nes.rom.GetPROM();
                return pPtr[0x2000 * 8 + 0x1000 + (addr - 0x5000)];
            }
            return (BYTE)(addr >> 8);
        }

        //void Mapper043::ExWrite(WORD addr, BYTE data)
        public override void ExWrite(ushort addr, byte data)
        {
            if ((addr & 0xF0FF) == 0x4022)
            {
                switch (data & 0x07)
                {
                    case 0x00:
                    case 0x02:
                    case 0x03:
                    case 0x04:
                        SetPROM_8K_Bank(6, 4);
                        break;
                    case 0x01:
                        SetPROM_8K_Bank(6, 3);
                        break;
                    case 0x05:
                        SetPROM_8K_Bank(6, 7);
                        break;
                    case 0x06:
                        SetPROM_8K_Bank(6, 5);
                        break;
                    case 0x07:
                        SetPROM_8K_Bank(6, 6);
                        break;
                }
            }
        }

        //void Mapper043::WriteLow(WORD addr, BYTE data)
        public override void WriteLow(ushort addr, byte data)
        {
            if ((addr & 0xF0FF) == 0x4022)
            {
                ExWrite(addr, data);
            }
        }

        //void Mapper043::Write(WORD addr, BYTE data)
        public override void Write(ushort addr, byte data)
        {
            if (addr == 0x8122)
            {
                if ((data & 0x03) != 0)
                {
                    irq_enable = 1;
                }
                else
                {
                    irq_counter = 0;
                    irq_enable = 0;
                }
                nes.cpu.ClrIRQ(IRQ_MAPPER);
            }
        }

        //void Mapper043::HSync(INT scanline)
        public override void HSync(int scanline)
        {
            nes.cpu.ClrIRQ(IRQ_MAPPER);
            if (irq_enable != 0)
            {
                irq_counter += 341;
                if (irq_counter >= 12288)
                {
                    irq_counter = 0;
                    //			nes.cpu.IRQ();
                    nes.cpu.SetIRQ(IRQ_MAPPER);
                }
            }
        }

        //void Mapper043::SaveState(LPBYTE p)
        public override void SaveState(byte[] p)
        {
            p[0] = irq_enable;
            //*(INT*)&p[1] = irq_counter;
            BitConverter.GetBytes(irq_counter).CopyTo(p, 1);
        }

        //void Mapper043::LoadState(LPBYTE p)
        public override void LoadState(byte[] p)
        {
            irq_enable = p[0];
            //irq_counter = *(INT*)&p[1];
            irq_counter = BitConverter.ToInt32(p, 1);
        }


        public override bool IsStateSave()
        {
            return true;
        }
    }
}