auto CPU::pio() -> uint8 {
  return status.pio;
}

auto CPU::joylatch() -> bool {
  return status.joypad_strobe_latch;
}

//WMDATA
auto CPU::mmio_r2180() -> uint8 {
  return bus.read(0x7e0000 | status.wram_addr++, regs.mdr);
}

//WMDATA
auto CPU::mmio_w2180(uint8 data) -> void {
  bus.write(0x7e0000 | status.wram_addr++, data);
}

//WMADDL
auto CPU::mmio_w2181(uint8 data) -> void {
  status.wram_addr = (status.wram_addr & 0x01ff00) | (data <<  0);
}

//WMADDM
auto CPU::mmio_w2182(uint8 data) -> void {
  status.wram_addr = (status.wram_addr & 0x0100ff) | (data <<  8);
}

//WMADDH
auto CPU::mmio_w2183(uint8 data) -> void {
  status.wram_addr = (status.wram_addr & 0x00ffff) | (data << 16);
}

//JOYSER0
//bit 0 is shared between JOYSER0 and JOYSER1, therefore
//strobing $4016.d0 affects both controller port latches.
//$4017 bit 0 writes are ignored.
auto CPU::mmio_w4016(uint8 data) -> void {
  device.controllerPort1->latch(data & 1);
  device.controllerPort2->latch(data & 1);
}

//JOYSER0
//7-2 = MDR
//1-0 = Joypad serial data
auto CPU::mmio_r4016() -> uint8 {
  uint8 r = regs.mdr & 0xfc;
  r |= device.controllerPort1->data();
  return r;
}

//JOYSER1
//7-5 = MDR
//4-2 = Always 1 (pins are connected to GND)
//1-0 = Joypad serial data
auto CPU::mmio_r4017() -> uint8 {
  uint8 r = (regs.mdr & 0xe0) | 0x1c;
  r |= device.controllerPort2->data();
  return r;
}

//NMITIMEN
auto CPU::mmio_w4200(uint8 data) -> void {
  status.auto_joypad_poll = data & 1;
  nmitimen_update(data);
}

//WRIO
auto CPU::mmio_w4201(uint8 data) -> void {
  if((status.pio & 0x80) && !(data & 0x80)) ppu.latch_counters();
  status.pio = data;
}

//WRMPYA
auto CPU::mmio_w4202(uint8 data) -> void {
  status.wrmpya = data;
}

//WRMPYB
auto CPU::mmio_w4203(uint8 data) -> void {
  status.rdmpy = 0;
  if(alu.mpyctr || alu.divctr) return;

  status.wrmpyb = data;
  status.rddiv = (status.wrmpyb << 8) | status.wrmpya;

  alu.mpyctr = 8;  //perform multiplication over the next eight cycles
  alu.shift = status.wrmpyb;
}

//WRDIVL
auto CPU::mmio_w4204(uint8 data) -> void {
  status.wrdiva = (status.wrdiva & 0xff00) | (data << 0);
}

//WRDIVH
auto CPU::mmio_w4205(uint8 data) -> void {
  status.wrdiva = (status.wrdiva & 0x00ff) | (data << 8);
}

//WRDIVB
auto CPU::mmio_w4206(uint8 data) -> void {
  status.rdmpy = status.wrdiva;
  if(alu.mpyctr || alu.divctr) return;

  status.wrdivb = data;

  alu.divctr = 16;  //perform division over the next sixteen cycles
  alu.shift = status.wrdivb << 16;
}

//HTIMEL
auto CPU::mmio_w4207(uint8 data) -> void {
  status.hirq_pos = (status.hirq_pos & 0x0100) | (data << 0);
}

//HTIMEH
auto CPU::mmio_w4208(uint8 data) -> void {
  status.hirq_pos = (status.hirq_pos & 0x00ff) | (data << 8);
}

//VTIMEL
auto CPU::mmio_w4209(uint8 data) -> void {
  status.virq_pos = (status.virq_pos & 0x0100) | (data << 0);
}

//VTIMEH
auto CPU::mmio_w420a(uint8 data) -> void {
  status.virq_pos = (status.virq_pos & 0x00ff) | (data << 8);
}

//DMAEN
auto CPU::mmio_w420b(uint8 data) -> void {
  for(unsigned i = 0; i < 8; i++) {
    channel[i].dma_enabled = data & (1 << i);
  }
  if(data) status.dma_pending = true;
}

//HDMAEN
auto CPU::mmio_w420c(uint8 data) -> void {
  for(unsigned i = 0; i < 8; i++) {
    channel[i].hdma_enabled = data & (1 << i);
  }
}

//MEMSEL
auto CPU::mmio_w420d(uint8 data) -> void {
  status.rom_speed = (data & 1 ? 6 : 8);
}

//RDNMI
//7   = NMI acknowledge
//6-4 = MDR
//3-0 = CPU (5a22) version
auto CPU::mmio_r4210() -> uint8 {
  uint8 r = (regs.mdr & 0x70);
  r |= (uint8)(rdnmi()) << 7;
  r |= (cpu_version & 0x0f);
  return r;
}

//TIMEUP
//7   = IRQ acknowledge
//6-0 = MDR
auto CPU::mmio_r4211() -> uint8 {
  uint8 r = (regs.mdr & 0x7f);
  r |= (uint8)(timeup()) << 7;
  return r;
}

//HVBJOY
//7   = VBLANK acknowledge
//6   = HBLANK acknowledge
//5-1 = MDR
//0   = JOYPAD acknowledge
auto CPU::mmio_r4212() -> uint8 {
  uint8 r = (regs.mdr & 0x3e);
  if(status.auto_joypad_active) r |= 0x01;
  if(hcounter() <= 2 || hcounter() >= 1096) r |= 0x40;  //hblank
  if(vcounter() >= (ppu.overscan() == false ? 225 : 240)) r |= 0x80;  //vblank
  return r;
}

//RDIO
auto CPU::mmio_r4213() -> uint8 {
  return status.pio;
}

//RDDIVL
auto CPU::mmio_r4214() -> uint8 {
  return status.rddiv >> 0;
}

//RDDIVH
auto CPU::mmio_r4215() -> uint8 {
  return status.rddiv >> 8;
}

//RDMPYL
auto CPU::mmio_r4216() -> uint8 {
  return status.rdmpy >> 0;
}

//RDMPYH
auto CPU::mmio_r4217() -> uint8 {
  return status.rdmpy >> 8;
}

auto CPU::mmio_r4218() -> uint8 { return status.joy1 >> 0; }  //JOY1L
auto CPU::mmio_r4219() -> uint8 { return status.joy1 >> 8; }  //JOY1H
auto CPU::mmio_r421a() -> uint8 { return status.joy2 >> 0; }  //JOY2L
auto CPU::mmio_r421b() -> uint8 { return status.joy2 >> 8; }  //JOY2H
auto CPU::mmio_r421c() -> uint8 { return status.joy3 >> 0; }  //JOY3L
auto CPU::mmio_r421d() -> uint8 { return status.joy3 >> 8; }  //JOY3H
auto CPU::mmio_r421e() -> uint8 { return status.joy4 >> 0; }  //JOY4L
auto CPU::mmio_r421f() -> uint8 { return status.joy4 >> 8; }  //JOY4H

//DMAPx
auto CPU::mmio_r43x0(uint8 i) -> uint8 {
  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);
}

//BBADx
auto CPU::mmio_r43x1(uint8 i) -> uint8 {
  return channel[i].dest_addr;
}

//A1TxL
auto CPU::mmio_r43x2(uint8 i) -> uint8 {
  return channel[i].source_addr >> 0;
}

//A1TxH
auto CPU::mmio_r43x3(uint8 i) -> uint8 {
  return channel[i].source_addr >> 8;
}

//A1Bx
auto CPU::mmio_r43x4(uint8 i) -> uint8 {
  return channel[i].source_bank;
}

//DASxL
//union { uint16 transfer_size; uint16 indirect_addr; };
auto CPU::mmio_r43x5(uint8 i) -> uint8 {
  return channel[i].transfer_size >> 0;
}

//DASxH
//union { uint16 transfer_size; uint16 indirect_addr; };
auto CPU::mmio_r43x6(uint8 i) -> uint8 {
  return channel[i].transfer_size >> 8;
}

//DASBx
auto CPU::mmio_r43x7(uint8 i) -> uint8 {
  return channel[i].indirect_bank;
}

//A2AxL
auto CPU::mmio_r43x8(uint8 i) -> uint8 {
  return channel[i].hdma_addr >> 0;
}

//A2AxH
auto CPU::mmio_r43x9(uint8 i) -> uint8 {
  return channel[i].hdma_addr >> 8;
}

//NTRLx
auto CPU::mmio_r43xa(uint8 i) -> uint8 {
  return channel[i].line_counter;
}

//???
auto CPU::mmio_r43xb(uint8 i) -> uint8 {
  return channel[i].unknown;
}

//DMAPx
auto CPU::mmio_w43x0(uint8 i, uint8 data) -> void {
  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;
}

//DDBADx
auto CPU::mmio_w43x1(uint8 i, uint8 data) -> void {
  channel[i].dest_addr = data;
}

//A1TxL
auto CPU::mmio_w43x2(uint8 i, uint8 data) -> void {
  channel[i].source_addr = (channel[i].source_addr & 0xff00) | (data << 0);
}

//A1TxH
auto CPU::mmio_w43x3(uint8 i, uint8 data) -> void {
  channel[i].source_addr = (channel[i].source_addr & 0x00ff) | (data << 8);
}

//A1Bx
auto CPU::mmio_w43x4(uint8 i, uint8 data) -> void {
  channel[i].source_bank = data;
}

//DASxL
//union { uint16 transfer_size; uint16 indirect_addr; };
auto CPU::mmio_w43x5(uint8 i, uint8 data) -> void {
  channel[i].transfer_size = (channel[i].transfer_size & 0xff00) | (data << 0);
}

//DASxH
//union { uint16 transfer_size; uint16 indirect_addr; };
auto CPU::mmio_w43x6(uint8 i, uint8 data) -> void {
  channel[i].transfer_size = (channel[i].transfer_size & 0x00ff) | (data << 8);
}

//DASBx
auto CPU::mmio_w43x7(uint8 i, uint8 data) -> void {
  channel[i].indirect_bank = data;
}

//A2AxL
auto CPU::mmio_w43x8(uint8 i, uint8 data) -> void {
  channel[i].hdma_addr = (channel[i].hdma_addr & 0xff00) | (data << 0);
}

//A2AxH
auto CPU::mmio_w43x9(uint8 i, uint8 data) -> void {
  channel[i].hdma_addr = (channel[i].hdma_addr & 0x00ff) | (data << 8);
}

//NTRLx
auto CPU::mmio_w43xa(uint8 i, uint8 data) -> void {
  channel[i].line_counter = data;
}

//???
auto CPU::mmio_w43xb(uint8 i, uint8 data) -> void {
  channel[i].unknown = data;
}

auto CPU::mmio_power() -> void {
}

auto CPU::mmio_reset() -> void {
  //$2140-217f
  for(auto& port : status.port) port = 0x00;

  //$2181-$2183
  status.wram_addr = 0x000000;

  //$4016-$4017
  status.joypad_strobe_latch = 0;
  status.joypad1_bits = ~0;
  status.joypad2_bits = ~0;

  //$4200
  status.nmi_enabled = false;
  status.hirq_enabled = false;
  status.virq_enabled = false;
  status.auto_joypad_poll = false;

  //$4201
  status.pio = 0xff;

  //$4202-$4203
  status.wrmpya = 0xff;
  status.wrmpyb = 0xff;

  //$4204-$4206
  status.wrdiva = 0xffff;
  status.wrdivb = 0xff;

  //$4207-$420a
  status.hirq_pos = 0x01ff;
  status.virq_pos = 0x01ff;

  //$420d
  status.rom_speed = 8;

  //$4214-$4217
  status.rddiv = 0x0000;
  status.rdmpy = 0x0000;

  //$4218-$421f
  status.joy1 = 0x0000;
  status.joy2 = 0x0000;
  status.joy3 = 0x0000;
  status.joy4 = 0x0000;

  //ALU
  alu.mpyctr = 0;
  alu.divctr = 0;
  alu.shift = 0;
}

auto CPU::mmio_read(uint addr, uint8 data) -> uint8 {
  addr &= 0xffff;

  //APU
  if((addr & 0xffc0) == 0x2140) {  //$2140-$217f
    synchronizeSMP();
    return smp.portRead(addr);
  }

  //DMA
  if((addr & 0xff80) == 0x4300) {  //$4300-$437f
    uint i = (addr >> 4) & 7;
    switch(addr & 0xf) {
    case 0x0: return mmio_r43x0(i);
    case 0x1: return mmio_r43x1(i);
    case 0x2: return mmio_r43x2(i);
    case 0x3: return mmio_r43x3(i);
    case 0x4: return mmio_r43x4(i);
    case 0x5: return mmio_r43x5(i);
    case 0x6: return mmio_r43x6(i);
    case 0x7: return mmio_r43x7(i);
    case 0x8: return mmio_r43x8(i);
    case 0x9: return mmio_r43x9(i);
    case 0xa: return mmio_r43xa(i);
    case 0xb: return mmio_r43xb(i);
    case 0xc: return regs.mdr;  //unmapped
    case 0xd: return regs.mdr;  //unmapped
    case 0xe: return regs.mdr;  //unmapped
    case 0xf: return mmio_r43xb(i);  //mirror of $43xb
    }
  }

  switch(addr) {
  case 0x2180: return mmio_r2180();
  case 0x4016: return mmio_r4016();
  case 0x4017: return mmio_r4017();
  case 0x4210: return mmio_r4210();
  case 0x4211: return mmio_r4211();
  case 0x4212: return mmio_r4212();
  case 0x4213: return mmio_r4213();
  case 0x4214: return mmio_r4214();
  case 0x4215: return mmio_r4215();
  case 0x4216: return mmio_r4216();
  case 0x4217: return mmio_r4217();
  case 0x4218: return mmio_r4218();
  case 0x4219: return mmio_r4219();
  case 0x421a: return mmio_r421a();
  case 0x421b: return mmio_r421b();
  case 0x421c: return mmio_r421c();
  case 0x421d: return mmio_r421d();
  case 0x421e: return mmio_r421e();
  case 0x421f: return mmio_r421f();
  }

  return data;
}

auto CPU::mmio_write(uint addr, uint8 data) -> void {
  addr &= 0xffff;

  //APU
  if((addr & 0xffc0) == 0x2140) {  //$2140-$217f
    synchronizeSMP();
    portWrite(addr, data);
    return;
  }

  //DMA
  if((addr & 0xff80) == 0x4300) {  //$4300-$437f
    uint i = (addr >> 4) & 7;
    switch(addr & 0xf) {
    case 0x0: mmio_w43x0(i, data); return;
    case 0x1: mmio_w43x1(i, data); return;
    case 0x2: mmio_w43x2(i, data); return;
    case 0x3: mmio_w43x3(i, data); return;
    case 0x4: mmio_w43x4(i, data); return;
    case 0x5: mmio_w43x5(i, data); return;
    case 0x6: mmio_w43x6(i, data); return;
    case 0x7: mmio_w43x7(i, data); return;
    case 0x8: mmio_w43x8(i, data); return;
    case 0x9: mmio_w43x9(i, data); return;
    case 0xa: mmio_w43xa(i, data); return;
    case 0xb: mmio_w43xb(i, data); return;
    case 0xc: return;  //unmapped
    case 0xd: return;  //unmapped
    case 0xe: return;  //unmapped
    case 0xf: mmio_w43xb(i, data); return;  //mirror of $43xb
    }
  }

  switch(addr) {
  case 0x2180: mmio_w2180(data); return;
  case 0x2181: mmio_w2181(data); return;
  case 0x2182: mmio_w2182(data); return;
  case 0x2183: mmio_w2183(data); return;
  case 0x4016: mmio_w4016(data); return;
  case 0x4017: return;  //unmapped
  case 0x4200: mmio_w4200(data); return;
  case 0x4201: mmio_w4201(data); return;
  case 0x4202: mmio_w4202(data); return;
  case 0x4203: mmio_w4203(data); return;
  case 0x4204: mmio_w4204(data); return;
  case 0x4205: mmio_w4205(data); return;
  case 0x4206: mmio_w4206(data); return;
  case 0x4207: mmio_w4207(data); return;
  case 0x4208: mmio_w4208(data); return;
  case 0x4209: mmio_w4209(data); return;
  case 0x420a: mmio_w420a(data); return;
  case 0x420b: mmio_w420b(data); return;
  case 0x420c: mmio_w420c(data); return;
  case 0x420d: mmio_w420d(data); return;
  }
}