R.Wieser
2024-02-15 11:04:28 UTC
Hello all,
I've got a small program going thru all video-modi by looping AL from 80
upto FF, calling INT 10, AH=00.
I would like to find out which of those modi are graphical. Ralf Browns
memory list shows 0040:0065 to hold some bits regarding the current video
mode. In my case the lower two bits are of interrest
Mode 03, text, shows the value 01. Alas, mode 0D, graphics, also shows 01.
In fact, only modi 4 thru 6 show a 02 there, and modi 0 and 01 show a 00.
Al others show 01.
And I'm pretty sure there are few other graphics modi above mode 06 ...
tl;dr:
How do I find out if a certain mode is graphics ?
Secondary question : if the lower two bits of 0040:0065 are *not* the
current video-modes graphics and textmode capablities, what do they signify
instead ?
## Bummer.
It turns out that selecting at least one video modus causes, on return to
it, my XP desktop to go black, with only the mouse visible & working. Than
after a few seconds the 'puter reboots.
In some other video modi enabeling the mouse causes an NTVDM illegal
instruction error.
Yet other video modi just display a black screen, which accepts neither text
output nor pixel plotting.
On short : even when INT 10h, AH=0Fh returns a selected video modus as
accepted, there is still a chance it won't work (and thats besides the -
expected - "out of range" and "no video signal" ones). :-(
Revised question:
How do I find all INT 10h, ah=00h video modi that wil actually work on my
(XP) 'puter ? (My "is it a graphical mode?" has become secondary).
Regards,
Rudy Wieser
I've got a small program going thru all video-modi by looping AL from 80
upto FF, calling INT 10, AH=00.
I would like to find out which of those modi are graphical. Ralf Browns
memory list shows 0040:0065 to hold some bits regarding the current video
mode. In my case the lower two bits are of interrest
Mode 03, text, shows the value 01. Alas, mode 0D, graphics, also shows 01.
In fact, only modi 4 thru 6 show a 02 there, and modi 0 and 01 show a 00.
Al others show 01.
And I'm pretty sure there are few other graphics modi above mode 06 ...
tl;dr:
How do I find out if a certain mode is graphics ?
Secondary question : if the lower two bits of 0040:0065 are *not* the
current video-modes graphics and textmode capablities, what do they signify
instead ?
## Bummer.
It turns out that selecting at least one video modus causes, on return to
it, my XP desktop to go black, with only the mouse visible & working. Than
after a few seconds the 'puter reboots.
In some other video modi enabeling the mouse causes an NTVDM illegal
instruction error.
Yet other video modi just display a black screen, which accepts neither text
output nor pixel plotting.
On short : even when INT 10h, AH=0Fh returns a selected video modus as
accepted, there is still a chance it won't work (and thats besides the -
expected - "out of range" and "no video signal" ones). :-(
Revised question:
How do I find all INT 10h, ah=00h video modi that wil actually work on my
(XP) 'puter ? (My "is it a graphical mode?" has become secondary).
Regards,
Rudy Wieser