Xref: utzoo comp.os.msdos.programmer:3082 comp.sys.ibm.pc.misc:6063
Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sun-barr!lll-winken!elroy.jpl.nasa.gov!sdd.hp.com!zaphod.mps.ohio-state.edu!rpi!masscomp!ocpt!tsdiag!jimb
From: jimb@tsdiag.ccur.com (Jim Blakey RG8U)
Newsgroups: comp.os.msdos.programmer,comp.sys.ibm.pc.misc
Subject: Request for assistance programming VGA
Keywords: VGA, graphics, pain, gnashing_of_teeth etc
Message-ID: <1435@tsdiag.ccur.com>
Date: 31 Jan 91 21:44:23 GMT
Organization: CONCURRENT,ENG. SERVICES,OCEANPORT NJ
Lines: 25


 A friend of mine and I are attempting to program VGA adapters
to display WEFAX images in 800x600x256 (or higher). We have the
hardware pretty well squared away, but we're having some trouble
with programming the VGA adapter on the bare metal. (There are 
rather stringent time constraints present - this beast is seriously
interrupt driven).  Are there any source-code examples of how to 
manipulate the VGA registers for the higher modes?  Has anyone
actually suceeded in figuring the VGA card out by reverse engineering?
Our main interest is in Trident chipset-derived cards, but info for
other ones may prove helpful as well.  Modes that require less than 64K 
(ie 320x200x256) work as expected.  Our color register setup routines work,
as well as the sum to grayscale command. We've tried INT 10H to put the card 
in the proper mode, but any and all attempts to jam data in the video RAM 
for modes that require more than 64K have resulted in seemingly random results.
Any information will be greatly appreciated, thank you in advance.
--
David E. Tiller         davet@tsdiag.ccur.com  | Concurrent Computer Corp.
FAX:  201-870-5952      Ph: (201) 870-4119 (w) | 2 Crescent Place, M/S 117
UUCP: ucbvax!rutgers!petsd!tsdiag!davet        | Oceanport NJ, 07757
ICBM: 40 16' 52" N      73 59' 00" W           | N2KAU @ NN2Z
and...
-- 
                       
              Jim Blakey    jimb@tsdiag.ccur.com