AxibugEmuOnline/Core/VirtualNes.Core/Mapper/Mapper109.cs

//////////////////////////////////////////////////////////////////////////
// Mapper109 SACHEN The Great Wall SA-019                               //
//////////////////////////////////////////////////////////////////////////
using static VirtualNes.MMU;
using BYTE = System.Byte;


namespace VirtualNes.Core
{
    public class Mapper109 : Mapper
    {

        BYTE reg;
        BYTE chr0, chr1, chr2, chr3;
        BYTE chrmode0, chrmode1;
        public Mapper109(NES parent) : base(parent)
        {
        }

        public override void Reset()
        {
            reg = 0;
            SetPROM_32K_Bank(0);

            chr0 = 0;
            chr1 = 0;
            chr2 = 0;
            chr3 = 0;
            SetBank_PPU();
            chrmode0 = 0;
            chrmode1 = 0;
        }

        //void Mapper109::WriteLow(WORD addr, BYTE data)
        public override void WriteLow(ushort addr, byte data)
        {
            switch (addr)
            {
                case 0x4100:
                    reg = data;
                    break;
                case 0x4101:
                    switch (reg)
                    {
                        case 0:
                            chr0 = data;
                            SetBank_PPU();
                            break;
                        case 1:
                            chr1 = data;
                            SetBank_PPU();
                            break;
                        case 2:
                            chr2 = data;
                            SetBank_PPU();
                            break;
                        case 3:
                            chr3 = data;
                            SetBank_PPU();
                            break;
                        case 4:
                            chrmode0 = (byte)(data & 0x01);
                            SetBank_PPU();
                            break;
                        case 5:
                            SetPROM_32K_Bank(data & 0x07);
                            break;
                        case 6:
                            chrmode1 = (byte)(data & 0x07);
                            SetBank_PPU();
                            break;
                        case 7:
                            if ((data & 0x01) != 0) SetVRAM_Mirror(VRAM_HMIRROR);
                            else SetVRAM_Mirror(VRAM_VMIRROR);
                            break;
                    }
                    break;
            }

        }

        void SetBank_PPU()
        {
            if (VROM_1K_SIZE != 0)
            {
                SetVROM_1K_Bank(0, chr0);
                SetVROM_1K_Bank(1, chr1 | ((chrmode1 << 3) & 0x8));
                SetVROM_1K_Bank(2, chr2 | ((chrmode1 << 2) & 0x8));
                SetVROM_1K_Bank(3, chr3 | ((chrmode1 << 1) & 0x8) | (chrmode0 * 0x10));
                SetVROM_1K_Bank(4, VROM_1K_SIZE - 4);
                SetVROM_1K_Bank(5, VROM_1K_SIZE - 3);
                SetVROM_1K_Bank(6, VROM_1K_SIZE - 2);
                SetVROM_1K_Bank(7, VROM_1K_SIZE - 1);
            }
        }

        //void Mapper109::SaveState(LPBYTE p)
        public override void SaveState(byte[] p)
        {
            p[0] = reg;
            p[1] = chr0;
            p[2] = chr1;
            p[3] = chr2;
            p[4] = chr3;
            p[5] = chrmode0;
            p[6] = chrmode1;
        }

        //void Mapper109::LoadState(LPBYTE p)
        public override void LoadState(byte[] p)
        {
            reg = p[0];
            chr0 = p[1];
            chr1 = p[2];
            chr2 = p[3];
            chr3 = p[4];
            chrmode0 = p[5];
            chrmode1 = p[6];
        }


        public override bool IsStateSave()
        {
            return true;
        }

    }
}