;bus = 0 to 255, device = 0 to 31, function = 0 to 7, index = 0 to 255
    mov eax,80000000h or (bus shl 16) or (device shl 11) or (function shl 8) or (index) ;we want to read dword at index 0
    mov dx,0cf8h
    out dx,eax
    mov dx 0cfch
    in eax,dx
;EAX low 16 bits = vendor ID, high 16 = device ID
;If vendor is FFFF there is no device there.
    

Function MemB(segm,offs:word):byte;assembler;
asm
movzx ebx,segm
shl ebx,4
movzx eax,offs
add ebx,eax
mov al,fs:[ebx]
end;

Function RMString(segm,offs:word;len:byte):string;
var a:longint;
    s:string;
begin
s:='';
for a:=0 to len-1 do s:=s+char(MemB(segm,offs+a));
RMstring:=s;
end;

Procedure Get_SVGA(var vendor,device:word);
var pci:word;
    ven,dev:word;
begin
vendor:=0;
device:=0;
pci:=word(MemB($C000,$18))+word(MemB($C000,$19))*256;
if RMstring($C000,pci,4)='PCIR' then
   begin
   vendor:=word(MemB($C000,pci+4))+word(MemB($C000,pci+5))*256;
   device:=word(MemB($C000,pci+6))+word(MemB($C000,pci+7))*256;
   end;
end;