Xref: utzoo comp.graphics:14364 comp.sys.ibm.pc.hardware:3011
Path: utzoo!attcan!uunet!cs.utexas.edu!ut-emx!jlange
From: jlange@ut-emx.uucp (John Lange)
Newsgroups: comp.graphics,comp.sys.ibm.pc.hardware
Subject: Re: Super VGA or 34010 scrolling by changing start address
Message-ID: <39534@ut-emx.uucp>
Date: 12 Nov 90 03:59:56 GMT
References: <39505@ut-emx.uucp>
Followup-To: poster
Organization: The University of Texas at Austin; Austin, Texas
Lines: 18

If anyone is interested, I figured out how to make 1024x768x256 scroll
using the Tseng ET4000 chip.

In article <39505@ut-emx.uucp>, jlange@emx.utexas.edu (John Lange) writes:
> to any place within the 1 MB of video memory.  Unfortunately, there are
> (seem to be) 18 bits of address space available to select the start
> address when 20 are really needed.  This mode is different than the
> other two in terms of how memory is organized.  With 1024x768x256, each
> byte represents a pixel (the bits in the byte represent the color planes).

The trick is that incrementing the start address by 1 increments the 
actual start address by 4!  Thus, 18 bits are all that are needed to 
address all 1 MB of video memory.

I'm still interested in anyone's comments about how to do the same thing
with the 34010.  I plan on calling TI tomorrow to try to find out, but
chances are we will use the Tseng chip since it is so much cheaper and
does what we want.