bsnes/snes/fast/cpu/mmio.cpp

#ifdef CPU_CPP

uint8 CPU::mmio_read(unsigned addr) {
  addr &= 0xffff;

  if((addr & 0xffc0) == 0x2140) {
    synchronize_smp();
    return smp.port_read(addr & 3);
  }

  if(addr == 0x2180) {
    uint8 result = bus.read(0x7e0000 | status.wram_addr);
    status.wram_addr = (status.wram_addr + 1) & 0x01ffff;
    return result;
  }

  if(addr == 0x4016) {
    uint8 result = regs.mdr & 0xfc;
    result |= input.port_read(0) & 3;
    return result;
  }

  if(addr == 0x4017) {
    uint8 result = (regs.mdr & 0xe0) | 0x1c;
    result |= input.port_read(1) & 3;
    return result;
  }

  if(addr == 0x4210) {
    uint8 result = (regs.mdr & 0x70);
    result |= status.nmi_line << 7;
    result |= 0x02;  //CPU revision
    status.nmi_line = false;
    return result;
  }

  if(addr == 0x4211) {
    uint8 result = (regs.mdr & 0x7f);
    result |= status.irq_line << 7;
    status.irq_line = false;
    return result;
  }

  if(addr == 0x4212) {
    uint8 result = (regs.mdr & 0x3e);
    unsigned vbstart = ppu.overscan() == false ? 225 : 240;

    if(vcounter() >= vbstart && vcounter() <= vbstart + 2) result |= 0x01;
    if(hcounter() <= 2 || hcounter() >= 1096) result |= 0x40;
    if(vcounter() >= vbstart) result |= 0x80;

    return result;
  }

  if(addr == 0x4213) return status.pio;

  if(addr == 0x4214) return status.rddiv >> 0;
  if(addr == 0x4215) return status.rddiv >> 8;
  if(addr == 0x4216) return status.rdmpy >> 0;
  if(addr == 0x4217) return status.rdmpy >> 8;

  if(addr == 0x4218) return status.joy1l;
  if(addr == 0x4219) return status.joy1h;
  if(addr == 0x421a) return status.joy2l;
  if(addr == 0x421b) return status.joy2h;
  if(addr == 0x421c) return status.joy3l;
  if(addr == 0x421d) return status.joy3h;
  if(addr == 0x421e) return status.joy4l;
  if(addr == 0x421f) return status.joy4h;

  if((addr & 0xff80) == 0x4300) {
    unsigned i = (addr >> 4) & 7;
    addr &= 0xff8f;

    if(addr == 0x4300) {
      return (channel[i].direction << 7)
           | (channel[i].indirect << 6)
           | (channel[i].unused << 5)
           | (channel[i].reverse_transfer << 4)
           | (channel[i].fixed_transfer << 3)
           | (channel[i].transfer_mode << 0);
    }

    if(addr == 0x4301) return channel[i].dest_addr;
    if(addr == 0x4302) return channel[i].source_addr >> 0;
    if(addr == 0x4303) return channel[i].source_addr >> 8;
    if(addr == 0x4304) return channel[i].source_bank;
    if(addr == 0x4305) return channel[i].transfer_size >> 0;
    if(addr == 0x4306) return channel[i].transfer_size >> 8;
    if(addr == 0x4307) return channel[i].indirect_bank;
    if(addr == 0x4308) return channel[i].hdma_addr >> 0;
    if(addr == 0x4309) return channel[i].hdma_addr >> 8;
    if(addr == 0x430a) return channel[i].line_counter;
    if(addr == 0x430b || addr == 0x430f) return channel[i].unknown;
  }

  return regs.mdr;
}

void CPU::mmio_write(unsigned addr, uint8 data) {
  addr &= 0xffff;

  if((addr & 0xffc0) == 0x2140) {
    synchronize_smp();
    port_write(addr & 3, data);
    return;
  }

  if(addr == 0x2180) {
    bus.write(0x7e0000 | status.wram_addr, data);
    status.wram_addr = (status.wram_addr + 1) & 0x01ffff;
    return;
  }

  if(addr == 0x2181) {
    status.wram_addr = (status.wram_addr & 0x01ff00) | (data << 0);
    return;
  }

  if(addr == 0x2182) {
    status.wram_addr = (status.wram_addr & 0x0100ff) | (data << 8);
    return;
  }

  if(addr == 0x2183) {
    status.wram_addr = (status.wram_addr & 0x00ffff) | ((data & 1) << 16);
    return;
  }

  if(addr == 0x4016) {
    bool old_latch = status.joypad_strobe_latch;
    bool new_latch = data & 1;
    status.joypad_strobe_latch = new_latch;
    if(old_latch != new_latch) input.poll();
    return;
  }

  if(addr == 0x4200) {
    bool nmi_enabled = status.nmi_enabled;
    bool virq_enabled = status.virq_enabled;
    bool hirq_enabled = status.hirq_enabled;

    status.nmi_enabled = data & 0x80;
    status.virq_enabled = data & 0x20;
    status.hirq_enabled = data & 0x10;
    status.auto_joypad_poll_enabled = data & 0x01;

    if(!nmi_enabled && status.nmi_enabled && status.nmi_line) {
      status.nmi_transition = true;
    }

    if(status.virq_enabled && !status.hirq_enabled && status.irq_line) {
      status.irq_transition = true;
    }

    if(!status.virq_enabled && !status.hirq_enabled) {
      status.irq_line = false;
      status.irq_transition = false;
    }

    status.irq_lock = true;
    return;
  }

  if(addr == 0x4201) {
    if((status.pio & 0x80) && !(data & 0x80)) ppu.latch_counters();
    status.pio = data;
  }

  if(addr == 0x4202) {
    status.wrmpya = data;
    return;
  }

  if(addr == 0x4203) {
    status.wrmpyb = data;
    status.rdmpy = status.wrmpya * status.wrmpyb;
    return;
  }

  if(addr == 0x4204) {
    status.wrdiva = (status.wrdiva & 0xff00) | (data << 0);
    return;
  }

  if(addr == 0x4205) {
    status.wrdiva = (data << 8) | (status.wrdiva & 0x00ff);
    return;
  }

  if(addr == 0x4206) {
    status.wrdivb = data;
    status.rddiv = status.wrdivb ? status.wrdiva / status.wrdivb : 0xffff;
    status.rdmpy = status.wrdivb ? status.wrdiva % status.wrdivb : status.wrdiva;
    return;
  }

  if(addr == 0x4207) {
    status.htime = (status.htime & 0x0100) | (data << 0);
    return;
  }

  if(addr == 0x4208) {
    status.htime = ((data & 1) << 8) | (status.htime & 0x00ff);
    return;
  }

  if(addr == 0x4209) {
    status.vtime = (status.vtime & 0x0100) | (data << 0);
    return;
  }

  if(addr == 0x420a) {
    status.vtime = ((data & 1) << 8) | (status.vtime & 0x00ff);
    return;
  }

  if(addr == 0x420b) {
    for(unsigned i = 0; i < 8; i++) channel[i].dma_enabled = data & (1 << i);
    if(data) dma_run();
    return;
  }

  if(addr == 0x420c) {
    for(unsigned i = 0; i < 8; i++) channel[i].hdma_enabled = data & (1 << i);
    return;
  }

  if(addr == 0x420d) {
    status.rom_speed = data & 1 ? 6 : 8;
    return;
  }

  if((addr & 0xff80) == 0x4300) {
    unsigned i = (addr >> 4) & 7;
    addr &= 0xff8f;

    if(addr == 0x4300) {
      channel[i].direction = data & 0x80;
      channel[i].indirect = data & 0x40;
      channel[i].unused = data & 0x20;
      channel[i].reverse_transfer = data & 0x10;
      channel[i].fixed_transfer = data & 0x08;
      channel[i].transfer_mode = data & 0x07;
      return;
    }

    if(addr == 0x4301) {
      channel[i].dest_addr = data;
      return;
    }

    if(addr == 0x4302) {
      channel[i].source_addr = (channel[i].source_addr & 0xff00) | (data << 0);
      return;
    }

    if(addr == 0x4303) {
      channel[i].source_addr = (data << 8) | (channel[i].source_addr & 0x00ff);
      return;
    }

    if(addr == 0x4304) {
      channel[i].source_bank = data;
      return;
    }

    if(addr == 0x4305) {
      channel[i].transfer_size = (channel[i].transfer_size & 0xff00) | (data << 0);
      return;
    }

    if(addr == 0x4306) {
      channel[i].transfer_size = (data << 8) | (channel[i].transfer_size & 0x00ff);
      return;
    }

    if(addr == 0x4307) {
      channel[i].indirect_bank = data;
      return;
    }

    if(addr == 0x4308) {
      channel[i].hdma_addr = (channel[i].hdma_addr & 0xff00) | (data << 0);
      return;
    }

    if(addr == 0x4309) {
      channel[i].hdma_addr = (data << 8) | (channel[i].hdma_addr & 0x00ff);
      return;
    }

    if(addr == 0x430a) {
      channel[i].line_counter = data;
      return;
    }

    if(addr == 0x430b || addr == 0x430f) {
      channel[i].unknown = data;
      return;
    }
  }
}

#endif