047.cpp

一个最快NFC的模拟器

/////////////////////////////////////////////////////////////////////
// Mapper 47
void NES_mapper47::Reset()
{
  patch= 0;

  if(parent_NES->crc32() == 0x7eef434c)   // Supare Mario Bros, Tetris, Nintendo World Cup
  {
    patch = 1;
  }

  // clear registers FIRST!!!
  for(int i = 0; i < 8; i++) regs[i] = 0x00;

  // set CPU bank pointers
  rom_bank = 0;
  prg0 = 0;
  prg1 = 1;
  MMC3_set_CPU_banks();

  // set VROM banks
  if(num_1k_VROM_banks)
  {
    chr01 = 0;
    chr23 = 2;
    chr4  = 4;
    chr5  = 5;
    chr6  = 6;
    chr7  = 7;
    MMC3_set_PPU_banks();
  }
  else
  {
    chr01 = chr23 = chr4 = chr5 = chr6 = chr7 = 0;
  }

  irq_enabled = 0;
  irq_counter = 0;
  irq_latch = 0;
}

void NES_mapper47::MemoryWriteSaveRAM(uint32 addr, uint8 data)
{
  if(addr == 0x6000)
  {
    if(patch)
    {
      rom_bank = (data & 0x06) >> 1;
    }
    else
    {
      rom_bank = (data & 0x01) << 1;
    }
    MMC3_set_CPU_banks();
    MMC3_set_PPU_banks();
  }
}

void NES_mapper47::MemoryWrite(uint32 addr, uint8 data)
{
  switch(addr & 0xE001)
  {
    case 0x8000:
      {
        regs[0] = data;
        MMC3_set_PPU_banks();
        MMC3_set_CPU_banks();
      }
      break;

    case 0x8001:
      {
        uint32 bank_num;
        regs[1] = data;
        bank_num = regs[1];

        switch(regs[0] & 0x07)
        {
          case 0x00:
            {
              if(num_1k_VROM_banks)
              {
                bank_num &= 0xfe;
                chr01 = bank_num;
                MMC3_set_PPU_banks();
              }
            }
            break;

          case 0x01:
            {
              if(num_1k_VROM_banks)
              {
                bank_num &= 0xfe;
                chr23 = bank_num;
                MMC3_set_PPU_banks();
              }
            }
            break;

          case 0x02:
            {
              if(num_1k_VROM_banks)
              {
                chr4 = bank_num;
                MMC3_set_PPU_banks();
              }
            }
            break;

          case 0x03:
            {
              if(num_1k_VROM_banks)
              {
                chr5 = bank_num;
                MMC3_set_PPU_banks();
              }
            }
            break;

          case 0x04:
            {
              if(num_1k_VROM_banks)
              {
                chr6 = bank_num;
                MMC3_set_PPU_banks();
              }
            }
            break;

          case 0x05:
            {
              if(num_1k_VROM_banks)
              {
                chr7 = bank_num;
                MMC3_set_PPU_banks();
              }
            }
            break;

          case 0x06:
            {
              prg0 = bank_num;
              MMC3_set_CPU_banks();
            }
            break;

          case 0x07:
            {
              prg1 = bank_num;
              MMC3_set_CPU_banks();
            }
            break;
        }
      }
      break;

    case 0xA000:
      {
        regs[2] = data;

        if(parent_NES->ROM->get_mirroring() != NES_PPU::MIRROR_FOUR_SCREEN)
        {
          if(data & 0x01)
          {
            set_mirroring(NES_PPU::MIRROR_HORIZ);
          }
          else
          {
            set_mirroring(NES_PPU::MIRROR_VERT);
          }
        }
      }
      break;

    case 0xA001:
      {
        regs[3] = data;
      }
      break;

    case 0xC000:
      regs[4] = data;
      irq_counter = regs[4];
      break;

    case 0xC001:
      regs[5] = data;
      irq_latch = regs[5];
      break;

    case 0xE000:
      regs[6] = data;
      irq_enabled = 0;
      break;

    case 0xE001:
      regs[7] = data;
      irq_enabled = 1;
      break;
  }
}

void NES_mapper47::HSync(uint32 scanline)
{
  if(irq_enabled)
  {
    if((scanline >= 0) && (scanline <= 239))
    {
      if(parent_NES->ppu->spr_enabled() || parent_NES->ppu->bg_enabled())
      {
        if(!(--irq_counter))
        {
          irq_counter = irq_latch;
          parent_NES->cpu->DoIRQ();
        }
      }
    }
  }
}

void NES_mapper47::MMC3_set_CPU_banks()
{
  if(prg_swap())
  {
    set_CPU_bank4(rom_bank * 8 + ((patch && rom_bank != 2) ? 6 : 14));
    set_CPU_bank5(rom_bank * 8 + prg1);
    set_CPU_bank6(rom_bank * 8 + prg0);
    set_CPU_bank7(rom_bank * 8 + ((patch && rom_bank != 2) ? 7 : 15));
  }
  else
  {
    set_CPU_bank4(rom_bank * 8 + prg0);
    set_CPU_bank5(rom_bank * 8 + prg1);
    set_CPU_bank6(rom_bank * 8 + ((patch && rom_bank != 2) ? 6 : 14));
    set_CPU_bank7(rom_bank * 8 + ((patch && rom_bank != 2) ? 7 : 15));
  }
}

void NES_mapper47::MMC3_set_PPU_banks()
{
  if(num_1k_VROM_banks)
  {
    if(chr_swap())
    {
      set_PPU_bank0((rom_bank & 0x02) * 64 + chr4);
      set_PPU_bank1((rom_bank & 0x02) * 64 + chr5);
      set_PPU_bank2((rom_bank & 0x02) * 64 + chr6);
      set_PPU_bank3((rom_bank & 0x02) * 64 + chr7);
      set_PPU_bank4((rom_bank & 0x02) * 64 + chr01 + 0);
      set_PPU_bank5((rom_bank & 0x02) * 64 + chr01 + 1);
      set_PPU_bank6((rom_bank & 0x02) * 64 + chr23 + 0);
      set_PPU_bank7((rom_bank & 0x02) * 64 + chr23 + 1);
    }
    else
    {
      set_PPU_bank0((rom_bank & 0x02) * 64 + chr01 + 0);
      set_PPU_bank1((rom_bank & 0x02) * 64 + chr01 + 1);
      set_PPU_bank2((rom_bank & 0x02) * 64 + chr23 + 0);
      set_PPU_bank3((rom_bank & 0x02) * 64 + chr23 + 1);
      set_PPU_bank4((rom_bank & 0x02) * 64 + chr4);
      set_PPU_bank5((rom_bank & 0x02) * 64 + chr5);
      set_PPU_bank6((rom_bank & 0x02) * 64 + chr6);
      set_PPU_bank7((rom_bank & 0x02) * 64 + chr7);
    }
  }
}
/////////////////////////////////////////////////////////////////////