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From: jst@cca.ucsf.edu (Joe Stong)
Newsgroups: comp.os.msdos.programmer
Subject: VGA programming
Message-ID: <3326@ucsfcca.ucsf.edu>
Date: 12 Jan 91 08:39:08 GMT
Reply-To: jst@cca.ucsf.edu (Joe Stong)
Organization: University of California, San Francisco
Lines: 34

Can anyone refer me to some good books or software collections
that include C code for doing direct hardware operations on a VGA?

I have the Norton/Wilton Displays book, and most of the examples are
in assembler.  I don't like the way that book is organized, either.

In particular I need to understand the "drill" necessary to access 
the display memory pages, and all of the crtc register settings necessary
to get the board into 800x600 or 1024x768 mode, WITHOUT using the BIOS
(I'm writing in Xenix, folks).  I got it right for the crtc registers
on a Hercules board, but I'm not even quite sure where to start on
the VGA (too many fiddily registers).

I also have the technical manual from Highland Technology, the
manufacturer of the VEGA VGA (8 bit) that I'm using.  I wasn't able
to understand from it how the "plane" scheme works, and what the
memory maps are in the various modes.  It also appears to gives
general description but not specific register settings for how to
set up for the high res modes.  Part of the problem is that I want
to have both a monochrome display adapter AND the VGA running at
the same time, for text menus, and graphic display, and it appears
that the VGA wants to try to do monochrome emulation, which I need
to disable.

Gee, what ever happened to the old days when someone would design
a I/O devies with a minimum of control registers, and considerations
for non-interference with other devices.  I guess I got raised on
some simple DEC I/O interfaces (that did their own DMA and didn't
try to emulate everything else they had ever built).

Please MAIL responses to me as well as posting, as I have trouble
keeping up with the _volume_ of messages in this section.

     Joe Stong   jst@cca.ucsf.edu