Date:	Fri, 2 Jun 1995 14:38:09 -0400 (EDT)
From:	James N Hormuzdiar <jimh AT minerva DOT cis DOT yale DOT edu>
To:	Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
Cc:	djgpp AT sun DOT soe DOT clarkson DOT edu
Subject:	Re: Graphics

On Thu, 25 May 1995, Eli Zaretskii wrote:

> >	3). Some places I have read claim I need a graphics driver?  I 
> > have always avoided using them, and just wrote directly to video memory 
> > (for speed).  Do I need one?
> 
> You do, unless your VGA supports VESA BIOS extensions.  The FAQ explains why.
> 
> > 	By the way- so far, I think I have set the mode correctly, but 
> > when I tried something like this-
> >
> >	asm("
> >		mov    $1, %ax;
> >		mov    $0xd0000000, %ebx;
> >		mov    ax, (%ebx);
> >	    ")
> >
> >	I just get a blank screen.
> 
> If you didn't call GrSetMode(), you won't get any results.  Again, explained
> in the FAQ.  Also, don't use hard-wired accesses, use the farptr functions as
> explained in the FAQ, because DJGPP v2.0 (the next release) won't allow the
> above code.

	Am I correct to then assume that I can not fill a screen using an 
assembly routine that directly stores data in it (rather than calling 
some other routine for each pixel/line/etc?  That would probably be too 
slow for what I am doing.  I am about to start looking through the 
source of the graphics library to better understand what is up, but would 
feel alot better if someone would clarify this for me before I end up 
wasting lots of time to find out djgpp won't do what I need.

						Thank you
							-Jim
 

- Raw text -