Re: bgi and widescreen

Jim Leonard wrote:
Jyrki Lahtonen wrote:
I'm out of my depth here, but I'm having similar troubles with
my new BenQ flat monitor and ASUS graphics card. They (don't know which
is to blame) won't give me modeX (320x240 256 colors) even though the
salesperson promised 100 per cent VGA compatible.

Most likely the monitor's fault. Hook up a real CRT to make sure.


Alas that didn't help (now that I finally had the time to try it out
properly).

To get a better idea what goes wrong I ran my code in the DPMI debugger.
The way my subroutine (cope/pasted from some web source) switches to
modeX appears to be that it first calls a BIOS interrupt $10 service
to switch to to regular mode $13 (320x200x256) and then starts tweaking
certain registers on the VGA card. The test run within the debugger
showed that this call to interrupt $10 does the damage: the screen turns
all black and the system hangs. Switching back to WinXP quickly follows
with an error message along the lines " the NT virtual DOS machine
encounterd an illegal instruction..."

Any ideas? Has the BIOS interrupt service $10 been discontinued for some
reason? This problem doesn't appear on the othe WinXP PC that I have
access to.

Cheers,

Jyrki
.