There are two configuration methods, depending on the PCI chipsets used:

Configuration Type 1:

CF8h D(R/W):
bit   0-7  Index into the configuration space to read/write at CFCh
    11-15  Card ID (0 - 31)
    16-19  PCI Bus ID (0 - 15)
       31  Set to enable the PCI bus configuration space

CFCh D(R/W):
bit  0-31  The index register identified by the PCI bus/card ID/Index in CF8h
           can be accessed here.


Configuration Type 2:

CF8h (R/W):
bit   7  Set to select the PCI configuration space

CFAh (R/W):
bit 0-?  Bus select ?


Finding the PCI devices:

  PCItype:=0;
  outp($CF8,0);
  outp($CFA,0);
  if (inp($CF8)=0) and (inp($CFA)=0) then PCItype:=2
  else begin
    tmp=inpl($CF8);
    outpl($CF8,$80000000);
    if inpl($CF8)=$80000000 then PCItype:=1;
    outpl($CF8,tmp);
  end;
  case PCItype of
    1:begin   {PCI type 1}
        for i:=0 to 511 do
        begin
          outpl($CF8,$80000000+i*longint(2048));
          tmp:=inpl($CFC);
          if ((tmp and $FFFF)<>$FFFF) and ((tmp shr 16)<>$FFFF) then
            _PCI Device: Vendor: (l and $FFFF)  Device: (l shr 16)_
        end;
      end;
    2:begin   {PCI type 2}
        outp($CF8,$80);
        outp($CFA,0);   {Bus select?}
        for i:=0 to 15 do
        begin
          tmp:=inpl(i*256 +$C000);
          if ((tmp and $FFFF)<>$FFFF) and ((tmp shr 16)<>$FFFF) then
            _PCI Device: Vendor: (l and $FFFF)  Device: (l shr 16)_
        end;
        outp($CF8,0);
      end;
  end;