simple program to locate ac97 in PCI space

hey all,

I'm working on a simple program to detect the mother board's sound card
(ac97). This program just takes the vendor and device id number and
checks to see if that device is present. On both a very old computer
(~1996) and a much newer one (~2005) my program says no ac97 found. It
could very well be an error somewhere in the program, but because i'm
unclear about the orgins of my device and vendor id #'s, i thought id
ask about them.

my include file (found on the net) gives me these Id's:



INTEL_VID equ 8086h ; Intel's PCI vendor ID
ICH_DID equ 2415h ; ICH device ID
ICH0_DID equ 2425h ; ICH0
ICH2_DID equ 2445h ; ICH2
ICH3_DID equ 2485h ; ICH3
ICH4_DID equ 24c5h ; ICH4
unknown equ 7195h

SIS_VID equ 1039h ; SIS PCI vendor ID
SI7012_DID equ 7012h ; SI7012

NVIDIA_VID equ 10deh ; NVIDIA vendor ID
NFORCE_DID equ 01b1h ; NFORCE

AMD_VID equ 1022h ; AMD vendor ID
AMD8111_DID equ 764dh ; AMD8111
AMD768_DID equ 7445h ; AMD768

the program looks for these devices with (half real fasm code, half
pseudo):

mov ax,"deviceid"
shl eax,16
mov ax,"Vendorid"
call pciFindDevice
jnc foundit
loop till all devices tried
jmp notfound

where pcifinddevice is known to work. I have no idea where to find
other vendor and device id's, and i assume all of these work according
to Intel 8201BA I/O Controller Hub (ICH2) AC97 Programmers reference
manual (http://www.intel.com/design/chipsets...s/29823801.pdf)

I should probably do more research on the differance between the
different ich's, but i assume atleast that ich4 (for instance) is
backwards compatible (is this a bad assumption?)

I'd like to make as robust a program as possible that supports as many
sound devices as is reasonable. Any information, suggestions, ideas,
etc are appreciated.

much thanks,
010 010