AxibugEmuOnline/AxibugEmuOnline.Client/Assets/VirtualNes.Core/Mapper/Mapper012.cs

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


namespace VirtualNes.Core
{
    public class Mapper012 : Mapper
    {
        uint vb0, vb1;
        BYTE[] reg = new byte[8];
        BYTE prg0, prg1;
        BYTE chr01, chr23, chr4, chr5, chr6, chr7;
        BYTE we_sram;

        BYTE irq_enable;
        BYTE irq_counter;
        BYTE irq_latch;
        BYTE irq_request;
        BYTE irq_preset;
        BYTE irq_preset_vbl;

        public Mapper012(NES parent) : base(parent) { }

        public override void Reset()
        {
            for (INT i = 0; i < 8; i++)
            {
                reg[i] = 0x00;
            }

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

            vb0 = 0;
            vb1 = 0;
            chr01 = 0;
            chr23 = 2;
            chr4 = 4;
            chr5 = 5;
            chr6 = 6;
            chr7 = 7;
            SetBank_PPU();

            we_sram = 0;    // Disable
            irq_enable = 0; // Disable
            irq_counter = 0;
            irq_latch = 0xFF;
            irq_request = 0;
            irq_preset = 0;
            irq_preset_vbl = 0;
        }

        //void Mapper012::WriteLow(WORD addr, BYTE data)
        public override void WriteLow(ushort addr, byte data)
        {
            if (addr > 0x4100 && addr < 0x6000)
            {
                vb0 = (byte)((data & 0x01) << 8);
                vb1 = (byte)((data & 0x10) << 4);
                SetBank_PPU();
            }
            else
            {
                base.WriteLow(addr, data);
            }
        }

        //BYTE Mapper012::ReadLow(WORD addr)
        public override byte ReadLow(ushort addr)
        {
            return 0x01;
        }

        //void Mapper012::Write(WORD addr, BYTE data)
        public override void Write(ushort addr, byte data)
        {
            //DEBUGOUT( "MPRWR A=%04X D=%02X L=%3d CYC=%d\n", addr&0xFFFF, data&0xFF, nes.GetScanline(), nes.cpu.GetTotalCycles() );

            switch (addr & 0xE001)
            {
                case 0x8000:
                    reg[0] = data;
                    SetBank_CPU();
                    SetBank_PPU();
                    break;
                case 0x8001:
                    reg[1] = data;

                    switch (reg[0] & 0x07)
                    {
                        case 0x00:
                            chr01 = (byte)(data & 0xFE);
                            SetBank_PPU();
                            break;
                        case 0x01:
                            chr23 = (byte)(data & 0xFE);
                            SetBank_PPU();
                            break;
                        case 0x02:
                            chr4 = data;
                            SetBank_PPU();
                            break;
                        case 0x03:
                            chr5 = data;
                            SetBank_PPU();
                            break;
                        case 0x04:
                            chr6 = data;
                            SetBank_PPU();
                            break;
                        case 0x05:
                            chr7 = data;
                            SetBank_PPU();
                            break;
                        case 0x06:
                            prg0 = data;
                            SetBank_CPU();
                            break;
                        case 0x07:
                            prg1 = data;
                            SetBank_CPU();
                            break;
                    }
                    break;
                case 0xA000:
                    reg[2] = data;
                    if (!nes.rom.Is4SCREEN())
                    {
                        if ((data & 0x01) != 0) SetVRAM_Mirror(VRAM_HMIRROR);
                        else SetVRAM_Mirror(VRAM_VMIRROR);
                    }
                    break;
                case 0xA001:
                    reg[3] = data;
                    break;
                case 0xC000:
                    reg[4] = data;
                    irq_latch = data;
                    break;
                case 0xC001:
                    reg[5] = data;
                    if (nes.GetScanline() < 240)
                    {
                        irq_counter |= 0x80;
                        irq_preset = 0xFF;
                    }
                    else
                    {
                        irq_counter |= 0x80;
                        irq_preset_vbl = 0xFF;
                        irq_preset = 0;
                    }
                    break;
                case 0xE000:
                    reg[6] = data;
                    irq_enable = 0;
                    irq_request = 0;

                    nes.cpu.ClrIRQ(IRQ_MAPPER);
                    break;
                case 0xE001:
                    reg[7] = data;
                    irq_enable = 1;
                    irq_request = 0;
                    break;
            }
        }

        //void Mapper012::HSync(INT scanline)
        public override void HSync(int scanline)
        {
            if ((scanline >= 0 && scanline <= 239) && nes.ppu.IsDispON())
            {
                if (irq_preset_vbl != 0)
                {
                    irq_counter = irq_latch;
                    irq_preset_vbl = 0;
                }
                if (irq_preset != 0)
                {
                    irq_counter = irq_latch;
                    irq_preset = 0;
                }
                else if (irq_counter > 0)
                {
                    irq_counter--;
                }

                if (irq_counter == 0)
                {
                    // Some game set irq_latch to zero to disable irq. So check it here.
                    if (irq_enable != 0 && irq_latch != 0)
                    {
                        irq_request = 0xFF;
                        nes.cpu.SetIRQ(IRQ_MAPPER);
                    }
                    irq_preset = 0xFF;
                }
            }
        }

        void SetBank_CPU()
        {
            if ((reg[0] & 0x40) != 0)
            {
                SetPROM_32K_Bank(PROM_8K_SIZE - 2, prg1, prg0, PROM_8K_SIZE - 1);
            }
            else
            {
                SetPROM_32K_Bank(prg0, prg1, PROM_8K_SIZE - 2, PROM_8K_SIZE - 1);
            }
        }

        void SetBank_PPU()
        {
            if (VROM_1K_SIZE != 0)
            {
                if ((reg[0] & 0x80) != 0)
                {
                    SetVROM_8K_Bank(
                        (int)(vb0 + chr4),
                        (int)(vb0 + chr5),
                        (int)(vb0 + chr6),
                        (int)(vb0 + chr7),
                        (int)(vb1 + chr01),
                        (int)(vb1 + chr01 + 1),
                        (int)(vb1 + chr23),
                        (int)(vb1 + chr23 + 1)
                        );
                }
                else
                {
                    SetVROM_8K_Bank(
                        (int)(vb0 + chr01),
                        (int)(vb0 + chr01 + 1),
                        (int)(vb0 + chr23),
                        (int)(vb0 + chr23 + 1),
                        (int)(vb1 + chr4),
                        (int)(vb1 + chr5),
                        (int)(vb1 + chr6),
                        (int)(vb1 + chr7))
                        ;
                }
            }
            else
            {
                if ((reg[0] & 0x80) != 0)
                {
                    SetCRAM_1K_Bank(4, (chr01 + 0) & 0x07);
                    SetCRAM_1K_Bank(5, (chr01 + 1) & 0x07);
                    SetCRAM_1K_Bank(6, (chr23 + 0) & 0x07);
                    SetCRAM_1K_Bank(7, (chr23 + 1) & 0x07);
                    SetCRAM_1K_Bank(0, chr4 & 0x07);
                    SetCRAM_1K_Bank(1, chr5 & 0x07);
                    SetCRAM_1K_Bank(2, chr6 & 0x07);
                    SetCRAM_1K_Bank(3, chr7 & 0x07);
                }
                else
                {
                    SetCRAM_1K_Bank(0, (chr01 + 0) & 0x07);
                    SetCRAM_1K_Bank(1, (chr01 + 1) & 0x07);
                    SetCRAM_1K_Bank(2, (chr23 + 0) & 0x07);
                    SetCRAM_1K_Bank(3, (chr23 + 1) & 0x07);
                    SetCRAM_1K_Bank(4, chr4 & 0x07);
                    SetCRAM_1K_Bank(5, chr5 & 0x07);
                    SetCRAM_1K_Bank(6, chr6 & 0x07);
                    SetCRAM_1K_Bank(7, chr7 & 0x07);
                }
            }
        }

        //void Mapper012::SaveState(LPBYTE p)
        public override void SaveState(byte[] p)
        {
            for (INT i = 0; i < 8; i++)
            {
                p[i] = reg[i];
            }
            p[8] = prg0;
            p[9] = prg1;
            p[10] = chr01;
            p[11] = chr23;
            p[12] = chr4;
            p[13] = chr5;
            p[14] = chr6;
            p[15] = chr7;
            p[16] = irq_enable;
            p[17] = (BYTE)irq_counter;
            p[18] = irq_latch;
            p[19] = irq_request;
            p[20] = irq_preset;
            p[21] = irq_preset_vbl;
            //*((DWORD*)&p[22]) = vb0;
            BitConverter.GetBytes(vb0).CopyTo(p,22);
            //*((DWORD*)&p[26]) = vb1;
            BitConverter.GetBytes(vb1).CopyTo(p,26);
        }

        //void Mapper012::LoadState(LPBYTE p)
        public override void LoadState(byte[] p)
        {
            for (INT i = 0; i < 8; i++)
            {
                reg[i] = p[i];
            }
            prg0 = p[8];
            prg1 = p[9];
            chr01 = p[10];
            chr23 = p[11];
            chr4 = p[12];
            chr5 = p[13];
            chr6 = p[14];
            chr7 = p[15];
            irq_enable = p[16];
            irq_counter = (byte)p[17];
            irq_latch = p[18];
            irq_request = p[19];
            irq_preset = p[20];
            irq_preset_vbl = p[21];
            //vb0 = *((DWORD*)&p[22]);
            vb0 = BitConverter.ToUInt32(p, 22);
            //vb1 = *((DWORD*)&p[26]);
            vb1 = BitConverter.ToUInt32(p, 26);
        }


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