[comp.sys.ibm.pc] Want software fix for 31.5KHz only monitor and VGA card

keithl@loop.UUCP (Keith Lofstrom) (07/28/89)

I have an Everex EV673 extended VGA card and a 31.5 KHz (only) color
monitor.   The dipswitch options on the EV673 expect either an EGA
or a Multisync monitor, and I have had 90% success with the card in
Multisync mode.  10% of the programs try to force EGA mode, which makes
my monitor lose H sync.  I am pretty sure a software fix exists.  Has
anybody got one?


More details:

I have spent the last few days hacking up a TSR that intercepts the INT 10h
video bios interrupt and changes the mode set function (and the various status
check functions).  Specifically, when it sees an INT 10h with ax=0010h,
it changes it to mode 12 and does various plausible things with the
CRTC registers. 

This makes Microsoft Flight Simulator work in a slightly distorted 640x350
VGA mode (the normal "VGA" driver is actually an EGA driver!).  Better than
the 640x200 mode!

Unfortunately, when I try the recently posted space flight simulator SFS,
it sorta works, but hacks up the display as if it was using multiple video
pages that overlap in memory a little (?!).  

So, I'm part way there, and I've seen enough to suspect a complete job can
be done, after many more days of experimentation.  If anyone has already
done this, it could save me some time.

BTW, I have been using the "Programmers Guide to PC and PS/2 Video Systems"
by Richard Wilton.  Kinda weak on register programming details, internals
of BIOS interrupts, etc., and the program listings in light green are going
to blind me.  Are there any better hardware-oriented works out there?

Pardon my rambling, and thanks for your attention,
-- 
Keith Lofstrom    keithl@loop    tektronix!tessi!qiclab!loop!keithl
Launch Loop, P.O. Box 1538, Portland, Oregon 97207   (503)-628-3645