bsnes/higan/fc/cartridge/board/bandai-fcg.cpp

//BANDAI-FCG

struct BandaiFCG : Board {
  BandaiFCG(Markup::Node& document) : Board(document) {
  }

  auto main() -> void {
    while(true) {
      if(scheduler.sync == Scheduler::SynchronizeMode::All) {
        scheduler.exit(Scheduler::ExitReason::SynchronizeEvent);
      }

      if(irq_counter_enable) {
        if(--irq_counter == 0xffff) {
          cpu.set_irq_line(1);
          irq_counter_enable = false;
        }
      }

      tick();
    }
  }

  auto ciram_addr(uint addr) const -> uint {
    switch(mirror) {
    case 0: return ((addr & 0x0400) >> 0) | (addr & 0x03ff);
    case 1: return ((addr & 0x0800) >> 1) | (addr & 0x03ff);
    case 2: return 0x0000 | (addr & 0x03ff);
    case 3: return 0x0400 | (addr & 0x03ff);
    }
  }

  auto prg_read(uint addr) -> uint8 {
    if(addr & 0x8000) {
      bool region = addr & 0x4000;
      uint bank = (region == 0 ? prg_bank : 0x0f);
      return prgrom.read((bank << 14) | (addr & 0x3fff));
    }
    return cpu.mdr();
  }

  auto prg_write(uint addr, uint8 data) -> void {
    if(addr >= 0x6000) {
      switch(addr & 15) {
      case 0x00: case 0x01: case 0x02: case 0x03:
      case 0x04: case 0x05: case 0x06: case 0x07:
        chr_bank[addr & 7] = data;
        break;
      case 0x08:
        prg_bank = data & 0x0f;
        break;
      case 0x09:
        mirror = data & 0x03;
        break;
      case 0x0a:
        cpu.set_irq_line(0);
        irq_counter_enable = data & 0x01;
        irq_counter = irq_latch;
        break;
      case 0x0b:
        irq_latch = (irq_latch & 0xff00) | (data << 0);
        break;
      case 0x0c:
        irq_latch = (irq_latch & 0x00ff) | (data << 8);
        break;
      case 0x0d:
        //TODO: serial EEPROM support
        break;
      }
    }
  }

  auto chr_read(uint addr) -> uint8 {
    if(addr & 0x2000) return ppu.ciram_read(ciram_addr(addr));
    addr = (chr_bank[addr >> 10] << 10) | (addr & 0x03ff);
    return Board::chr_read(addr);
  }

  auto chr_write(uint addr, uint8 data) -> void {
    if(addr & 0x2000) return ppu.ciram_write(ciram_addr(addr), data);
    addr = (chr_bank[addr >> 10] << 10) | (addr & 0x03ff);
    return Board::chr_write(addr, data);
  }

  auto power() -> void {
    reset();
  }

  auto reset() -> void {
    for(auto &n : chr_bank) n = 0;
    prg_bank = 0;
    mirror = 0;
    irq_counter_enable = 0;
    irq_counter = 0;
    irq_latch = 0;
  }

  auto serialize(serializer& s) -> void {
    Board::serialize(s);

    s.array(chr_bank);
    s.integer(prg_bank);
    s.integer(mirror);
    s.integer(irq_counter_enable);
    s.integer(irq_counter);
    s.integer(irq_latch);
  }

  uint8 chr_bank[8];
  uint8 prg_bank;
  uint2 mirror;
  bool irq_counter_enable;
  uint16 irq_counter;
  uint16 irq_latch;
};