AxibugEmuOnline/AxibugEmuOnline.Client/Assets/VirtualNes.Core/Mapper/Mapper042.cs

//////////////////////////////////////////////////////////////////////////
// Mapper042  Mario Baby                                                //
//////////////////////////////////////////////////////////////////////////
using static VirtualNes.Core.CPU;
using static VirtualNes.MMU;
using BYTE = System.Byte;


namespace VirtualNes.Core
{
    public class Mapper042 : Mapper
    {
        BYTE irq_enable;
        BYTE irq_counter;
        public Mapper042(NES parent) : base(parent)
        {
        }


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

            SetPROM_8K_Bank(3, 0);
            SetPROM_32K_Bank(PROM_8K_SIZE - 4, PROM_8K_SIZE - 3, PROM_8K_SIZE - 2, PROM_8K_SIZE - 1);

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

        //void Mapper042::Write(WORD addr, BYTE data)
        public override void Write(ushort addr, byte data)
        {
            switch (addr & 0xE003)
            {
                case 0xE000:
                    SetPROM_8K_Bank(3, data & 0x0F);
                    break;

                case 0xE001:
                    if ((data & 0x08) != 0) SetVRAM_Mirror(VRAM_HMIRROR);
                    else SetVRAM_Mirror(VRAM_VMIRROR);
                    break;

                case 0xE002:
                    if ((data & 0x02) != 0)
                    {
                        irq_enable = 0xFF;
                    }
                    else
                    {
                        irq_enable = 0;
                        irq_counter = 0;
                    }
                    nes.cpu.ClrIRQ(IRQ_MAPPER);
                    break;
            }
        }

        //void Mapper042::HSync(INT scanline)
        public override void HSync(int scanline)
        {
            nes.cpu.ClrIRQ(IRQ_MAPPER);
            if (irq_enable != 0)
            {
                if (irq_counter < 215)
                {
                    irq_counter++;
                }
                if (irq_counter == 215)
                {
                    irq_enable = 0;
                    //			nes.cpu.IRQ();
                    nes.cpu.SetIRQ(IRQ_MAPPER);
                }
            }
        }

        //void Mapper042::SaveState(LPBYTE p)
        public override void SaveState(byte[] p)
        {
            p[0] = irq_enable;
            p[1] = irq_counter;
        }

        //void Mapper042::LoadState(LPBYTE p)
        public override void LoadState(byte[] p)
        {
            irq_enable = p[0];
            irq_counter = p[1];
        }


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