U32 PCIReadU32(I64 bus, I64 dev, I64 fun, I64 rg)
{//Read U32 in PCI configspace at bus, dev, fun, reg.
  I64 res, addr, offset;
  if (sys_pci_services)
    res = PCIBIOSReadU32(bus, dev, fun, rg);
  else
  {
    addr =      bus << 16       |
        dev << 11       |
        fun << 8        |
        rg & 0xFC       |
        0x80000000;
    offset = rg - rg & 0xFC;
    OutU32(PCI_ADDR, addr);
    res = InU32(PCI_DATA) >> (offset * 8);
  }
  return res;
}

U8 PCIReadU8(I64 bus, I64 dev, I64 fun, I64 rg)
{//Read U8 in PCI configspace at bus, dev, fun, reg.
  I64 res;
  if (sys_pci_services)
    res = PCIBIOSReadU8(bus, dev, fun, rg);
  else
  {
    res = PCIReadU32(bus, dev, fun, rg) & 0xFF;
  }
  return res;
}

U16 PCIReadU16(I64 bus, I64 dev, I64 fun, I64 rg)
{//Read U16 in PCI configspace at bus, dev, fun, reg.
  I64 res;
  if (sys_pci_services)
    res = PCIBIOSReadU16(bus, dev, fun, rg);
  else
  {
    res = PCIReadU32(bus, dev, fun, rg) & 0xFFFF;
  }
  return res;
}

U0 PCIWriteU32(I64 bus, I64 dev, I64 fun, I64 rg, I64 val)
{//Write U32 in PCI configspace at bus, dev, fun, reg.
  I64 addr, offset;
  if (sys_pci_services)
    PCIBIOSWriteU32(bus, dev, fun, rg, val);
  else
  {
    addr =      bus << 16       |
        dev << 11       |
        fun << 8        |
        rg & 0xFC       |
        0x80000000;
    offset = rg - rg & 0xFC;
    OutU32(PCI_ADDR, addr);
    OutU32(PCI_DATA, val << (offset * 8));
  }
}


U0 PCIWriteU8(I64 bus, I64 dev, I64 fun, I64 rg, I64 val)
{//Write U8 in PCI configspace at bus, dev, fun, reg.
  if (sys_pci_services)
    PCIBIOSWriteU8(bus, dev, fun, rg, val);
  else
  {
    PCIWriteU32(bus, dev, fun, rg, val & 0xFF);
  }
}

U0 PCIWriteU16(I64 bus, I64 dev, I64 fun, I64 rg, I64 val)
{//Write U16 in PCI configspace at bus, dev, fun, reg.
  if (sys_pci_services)
    PCIBIOSWriteU16(bus, dev, fun, rg, val);
  else
  {
    PCIWriteU32(bus, dev, fun, rg, val & 0xFFFF);
  }
}

I64 PCIClassFind(I64 class_code, I64 n)
{
  /*Find bus, dev, fun of Nth class_code dev.

  class_code is low three bytes
  n is index starting at zero
  Return: -1 not found
  else bus, dev, fun.
  */
  I64 res = -1, cur = 0, b, d, f;
  if (sys_pci_services)
  {
    res = PCIBIOSClassFind(class_code, n);
  }
  else
  {
    for (b = 0; b < sys_pci_busses; b++)
      for (d = 0; d < 32; d++)
        for (f = 0; f < 8; f++)
        {
          if (class_code == PCIReadU32(b, d, f, PCIR_PROG_IF) & 0xFFFFFF)
          {
            if (n == cur++)
            {
              res = b << 16 | d << 8 | f;
              goto pci_end;
            }
          }
        }
  }
pci_end:
  return res;
}

Bool PCIBt(U8 reg RBX *bit_field, I64 reg RDX bit)
{ // MOV-based Bt for use in PCI device MMIO areas.  See Bt().
  bit_field += bit / 8;
  bit &= 7;
  return (*bit_field & 1 << bit) >> bit;
}

Bool PCIBtr(U8 reg RDX *bit_field, I64 reg RBX bit)
{ // MOV-based Btr for use in PCI device MMIO areas.  See Btr().
  U64 reg R9 chunk_mod = bit & 31, chunk_bit = 1 << chunk_mod;
  bit_field(U32 *) += bit / 32;
  Bool reg R8 result = (*bit_field(U32 *) & chunk_bit) >> chunk_mod;

  *bit_field(U32 *) &= ~chunk_bit;

  return result;
}

Bool PCIBts(U8 reg RDX *bit_field, I64 reg RBX bit)
{ // MOV-based Bts for use in PCI device MMIO areas.  See Bts().
  U64 reg R9 chunk_mod = bit & 31, chunk_bit = 1 << chunk_mod;
  bit_field(U32 *) += bit / 32;
  Bool reg R8 result = (*bit_field(U32 *) & chunk_bit) >> chunk_mod;

  *bit_field(U32 *) |= chunk_bit;

  return result;
}