AxibugEmuOnline/AxibugEmuOnline.Client/Assets/VirtualNes.Core/Mapper/Mapper112.cs

//////////////////////////////////////////////////////////////////////////
// Mapper112  Nintendo MMC3                                             //
//////////////////////////////////////////////////////////////////////////
using static VirtualNes.MMU;
using BYTE = System.Byte;
using INT = System.Int32;


namespace VirtualNes.Core
{
    public class Mapper112 : Mapper
    {
        BYTE[] reg = new byte[4];
        BYTE prg0, prg1;
        BYTE chr01, chr23, chr4, chr5, chr6, chr7;
        public Mapper112(NES parent) : base(parent)
        {
        }

        public override void Reset()
        {
            for (INT i = 0; i < 4; i++)
            {
                reg[i] = 0x00;
            }

            prg0 = 0;
            prg1 = 1;
            SetBank_CPU();

            chr01 = 0;
            chr23 = 2;
            chr4 = 4;
            chr5 = 5;
            chr6 = 6;
            chr7 = 7;
            SetBank_PPU();
        }

        //void Mapper112::Write(WORD addr, BYTE data)
        public override void Write(ushort addr, byte data)
        {
            switch (addr)
            {
                case 0x8000:
                    reg[0] = data;
                    SetBank_CPU();
                    SetBank_PPU();
                    break;
                case 0xA000:
                    reg[1] = data;
                    switch (reg[0] & 0x07)
                    {
                        case 0x00:
                            prg0 = (byte)((data & (PROM_8K_SIZE - 1)));
                            SetBank_CPU();
                            break;
                        case 0x01:
                            prg1 = (byte)((data & (PROM_8K_SIZE - 1)));
                            SetBank_CPU();
                            break;
                        case 0x02:
                            chr01 = (byte)(data & 0xFE);
                            SetBank_PPU();
                            break;
                        case 0x03:
                            chr23 = (byte)(data & 0xFE);
                            SetBank_PPU();
                            break;
                        case 0x04:
                            chr4 = data;
                            SetBank_PPU();
                            break;
                        case 0x05:
                            chr5 = data;
                            SetBank_PPU();
                            break;
                        case 0x06:
                            chr6 = data;
                            SetBank_PPU();
                            break;
                        case 0x07:
                            chr7 = data;
                            SetBank_PPU();
                            break;
                    }
                    break;

                case 0xC000:
                    reg[3] = data;
                    SetBank_PPU();
                    break;//hum 源码居然没有break 语法差异呗
                case 0xE000:
                    reg[2] = data;
                    if (!nes.rom.Is4SCREEN())
                    {
                        if ((data & 0x01) != 0) SetVRAM_Mirror(VRAM_HMIRROR);
                        else SetVRAM_Mirror(VRAM_VMIRROR);
                    }
                    SetBank_PPU();
                    break;
            }
        }

        void SetBank_CPU()
        {
            SetPROM_32K_Bank(prg0, prg1, PROM_8K_SIZE - 2, PROM_8K_SIZE - 1);
        }

        void SetBank_PPU()
        {
            if ((reg[2] & 0x02) != 0)
            {
                SetVROM_8K_Bank(chr01, chr01 + 1, chr23, chr23 + 1, chr4, chr5, chr6, chr7);
            }
            else
            {
                SetVROM_8K_Bank(((reg[3] << 6) & 0x100) + chr01,
                        ((reg[3] << 6) & 0x100) + chr01 + 1,
                        ((reg[3] << 5) & 0x100) + chr23,
                        ((reg[3] << 5) & 0x100) + chr23 + 1,
                        ((reg[3] << 4) & 0x100) + chr4,
                        ((reg[3] << 3) & 0x100) + chr5,
                        ((reg[3] << 2) & 0x100) + chr6,
                        ((reg[3] << 1) & 0x100) + chr7);
            }
        }

        //void Mapper112::SaveState(LPBYTE p)
        public override void SaveState(byte[] p)
        {
            for (INT i = 0; i < 4; i++)
            {
                p[i] = reg[i];
            }
            p[4] = chr01;
            p[5] = chr23;
            p[6] = chr4;
            p[7] = chr5;
            p[8] = chr6;
            p[9] = chr7;
        }

        //void Mapper112::LoadState(LPBYTE p)
        public override void LoadState(byte[] p)
        {
            for (byte i = 0; i < 4; i++)
            {
                reg[i] = p[i];
            }

            chr01 = p[4];
            chr23 = p[5];
            chr4 = p[6];
            chr5 = p[7];
            chr6 = p[8];
            chr7 = p[9];
        }

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