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alexbevi
GitHub Repository: alexbevi/BizHawk
 Path: blob/master/libsnes/bsnes/gameboy/cartridge/mbc3/mbc3.cpp
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#ifdef CARTRIDGE_CPP

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void Cartridge::MBC3::second() {

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  if(rtc_halt == false) {

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    if(++rtc_second >= 60) {

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      rtc_second = 0;

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      if(++rtc_minute >= 60) {

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        rtc_minute = 0;

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        if(++rtc_hour >= 24) {

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          rtc_hour = 0;

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          if(++rtc_day >= 512) {

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            rtc_day = 0;

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            rtc_day_carry = true;

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          }

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        }

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      }

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    }

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  }

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}

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uint8 Cartridge::MBC3::mmio_read(uint16 addr) {

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  if((addr & 0xc000) == 0x0000) {  //$0000-3fff

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    return cartridge.rom_read(addr);

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  }

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  if((addr & 0xc000) == 0x4000) {  //$4000-7fff

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    return cartridge.rom_read((rom_select << 14) | (addr & 0x3fff));

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  }

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  if((addr & 0xe000) == 0xa000) {  //$a000-bfff

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    if(ram_enable) {

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      if(ram_select >= 0x00 && ram_select <= 0x03) {

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        return cartridge.ram_read((ram_select << 13) | (addr & 0x1fff));

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      }

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      if(ram_select == 0x08) return rtc_latch_second;

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      if(ram_select == 0x09) return rtc_latch_minute;

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      if(ram_select == 0x0a) return rtc_latch_hour;

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      if(ram_select == 0x0b) return rtc_latch_day;

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      if(ram_select == 0x0c) return (rtc_latch_day_carry << 7) | (rtc_latch_day >> 8);

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    }

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    return 0x00;

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  }

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  return 0x00;

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}

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void Cartridge::MBC3::mmio_write(uint16 addr, uint8 data) {

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  if((addr & 0xe000) == 0x0000) {  //$0000-1fff

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    ram_enable = (data & 0x0f) == 0x0a;

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    return;

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  }

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  if((addr & 0xe000) == 0x2000) {  //$2000-3fff

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    rom_select = (data & 0x7f) + ((data & 0x7f) == 0);

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    return;

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  }

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  if((addr & 0xe000) == 0x4000) {  //$4000-5fff

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    ram_select = data;

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    return;

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  }

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  if((addr & 0xe000) == 0x6000) {  //$6000-7fff

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    if(rtc_latch == 0 && data == 1) {

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      rtc_latch_second = rtc_second;

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      rtc_latch_minute = rtc_minute;

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      rtc_latch_hour = rtc_hour;

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      rtc_latch_day = rtc_day;

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      rtc_latch_day_carry = rtc_day_carry;

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    }

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    rtc_latch = data;

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    return;

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  }

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  if((addr & 0xe000) == 0xa000) {  //$a000-bfff

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    if(ram_enable) {

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      if(ram_select >= 0x00 && ram_select <= 0x03) {

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        cartridge.ram_write((ram_select << 13) | (addr & 0x1fff), data);

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      } else if(ram_select == 0x08) {

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        if(data >= 60) data = 0;

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        rtc_second = data;

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      } else if(ram_select == 0x09) {

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        if(data >= 60) data = 0;

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        rtc_minute = data;

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      } else if(ram_select == 0x0a) {

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        if(data >= 24) data = 0;

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        rtc_hour = data;

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      } else if(ram_select == 0x0b) {

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        rtc_day = (rtc_day & 0x0100) | data;

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      } else if(ram_select == 0x0c) {

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        rtc_day = ((data & 1) << 8) | (rtc_day & 0xff);

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        rtc_halt = data & 0x40;

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        rtc_day_carry = data & 0x80;

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      }

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    }

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    return;

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  }

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}

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void Cartridge::MBC3::power() {

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  ram_enable = false;

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  rom_select = 0x01;

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  ram_select = 0x00;

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  rtc_latch = 0;

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  rtc_halt = true;

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  rtc_second = 0;

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  rtc_minute = 0;

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  rtc_hour = 0;

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  rtc_day = 0;

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  rtc_day_carry = false;

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  rtc_latch_second = 0;

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  rtc_latch_minute = 0;

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  rtc_latch_hour = 0;

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  rtc_latch_day = 0;

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  rtc_latch_day_carry = false;

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}

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#endif

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