SVGA, information wanted

Thread View: alt.msdos.programmer

4 messages

[T] Back to Threads [V] Tree View [G] Group Articles

4 total messages Started by ANDREAS ARFF Tue, 27 Oct 1992 10:41

Author: ANDREAS ARFF
Date: Tue, 27 Oct 1992 10:41

24 lines
1611 bytes

Hi netters

I'd like to get some information on how to get SVGA screen modes.

I have tried to use 0x4F02, int 10, but it doesn't seem to work.
I have also noticed that you can get information about the supported modes
using 0x4F01, int 10.
(Credit to Ralph Brown, but his interrupt list doesn't give all the 
answers:-)
What I'd like to know is: How do you find out which modes are 
available, and how do you initialize SVGA modes. I'd also like to know if 
there are bitplanes, how you address a pixel on the screen and if there are 
any pages etc.

If someone had a description of this, an ftp cite where a could get this 
info., or assembly/C code, I'd become very thanksful.

Arff - andreasa@dhhalden.no
"Also for the not religous confessor, there is a mystery of higher values,
who's birth mankind - to the last - builds upon. They are indisputible. And 
often disregarded. Seldom you hear them beeing prized, as seldom as you hear 
a seeing man prizeing what he sees." Per Lagerkvist, The Fist 
(Free translation from Swedish)
              --Andreas Arff  andreasa@dhhalden.no--

Re: SVGA, information wanted

Author: cslewis
Date: Tue, 27 Oct 1992 22:31

31 lines
1424 bytes

I've been doing some SVGA programming over the last few days.
I'll share with you all the little information I have.

int 10h, 4f01h gives SVGA mode information.  Set these registers:
	AX : 4f01h
	CX : SVGA mode #
	ES : segment of a 256 byte buffer where info is stored
	DI : offset of buffer
then call int 10h.

int 10h, 4f02h sets the SVGA mode, where BX is the mode number
(100h - ???).

I've been experimenting with mode 105h (1024 x 767 x 256 colors).
int 4f01h says that this mode uses 8 bits per byte, not bitplanes,
with 12 64k windows.  I'm trying to draw pixels using write mode 2
but they come out looking weird, as if there are bitplanes that I'm
not handling correctly.

Can anyone else give more information about working in SVGA mode?
Please post or email.  Otherwise, I can followup with some more
info.

-Scott Lewis
cslewis@vesta.unm.edu

-- 
---------------------
Scott Lewis
cslewis@vesta.unm.edu
---------------------

Re: SVGA, information wanted

Author: Joe Huffman
Date: Wed, 28 Oct 1992 11:06

34 lines
1540 bytes

cslewis@vesta.unm.edu () writes:

>I've been doing some SVGA programming over the last few days.
> ... stuff deleted...
>I've been experimenting with mode 105h (1024 x 767 x 256 colors).
>int 4f01h says that this mode uses 8 bits per byte, not bitplanes,
>with 12 64k windows.  I'm trying to draw pixels using write mode 2
>but they come out looking weird, as if there are bitplanes that I'm
>not handling correctly.

>Can anyone else give more information about working in SVGA mode?
>Please post or email.  Otherwise, I can followup with some more
>info.

For mode 105h, it is just put it into that mode, then write one byte for
each pixel.  Don't worry about 'write modes' and I/O ports and registers.

Get the VESA standard... it is a big help and it is free.

VESA
Suite 360
2150 North First Street
San Jose, CA 95131-2020

Voice: 408-435-0333
FAX:   408-435-8225

Or use a graphic library that supports VESA.  My company sells one -- if 
you are interested send me email with an snail mail address and we'll send
you a demo disk.

-- 
netcom!proto!joe
joe@proto.com

Re: SVGA, information wanted

Author: Scott Lewis
Date: Wed, 28 Oct 1992 18:21

46 lines
2014 bytes

In article <1992Oct28.110614.6898@proto.com> joe@proto.com (Joe Huffman) writes:
>
>For mode 105h, it is just put it into that mode, then write one byte for
>each pixel.  Don't worry about 'write modes' and I/O ports and registers.
>
>Get the VESA standard... it is a big help and it is free.
>

Thanks for the help, Joe.  It solved my problem right away.  I'll definitely
get the VESA standard, too.

In the meantime, though, I have another question for you or anyone else.
Int 4f01h (Return SVGA Mode Information) tells me how many bitplanes
each mode uses:
     100h : 1 bitplane
     101h : 1
     102h : 4
     103h : 1
     104h : 4
     105h : 1

Am I correct in assuming that for those modes with only one bitplane
I just set the mode and write one bit per pixel, as described above?
And for those with multiple bit planes I need to set the video mode
and write mode, and write thru the bit mask?

I have a book that gives a little information on VESA.  It says that
different video cards implement the standard in different ways- so
don't assume that what works on one card will work on others.  The
book says you must get the info from int 4f01h to find out how
the video card implements the specifics of each SVGA mode.  Is this
true?  Does that mean that the above info is correct for only some
video cards?

Thanks in advance for any help.

Scott Lewis
cslewis@vesta.unm.edu

-- 
---------------------
Scott Lewis
cslewis@vesta.unm.edu
---------------------

Thread Navigation

This is a paginated view of messages in the thread with full content displayed inline.

Messages are displayed in chronological order, with the original post highlighted in green.

Use pagination controls to navigate through all messages in large threads.

Back to All Threads