From: JAB <jab_joe AT my-deja DOT com>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: Screen Address in VESA 2.0
Date: Wed, 15 Sep 1999 09:59:04 GMT
Organization: Deja.com - Share what you know. Learn what you don't.
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In article <7rmnjl$9fd$1 AT solomon DOT cs DOT rose-hulman DOT edu>,
  "Damian Yerrick" <reply DOT at DOT your DOT own DOT risk AT pineight DOT 8m DOT com> wrote:
>
> JAB <jab_joe AT my-deja DOT com> wrote in message
> news:7rmff2$5rt$1 AT nnrp1 DOT deja DOT com...
> > Hiya
> >
> >  I've written a 3D thing on my dear old StrongARM RPC.
>
> That's the same CPU that Apple used in Newton.

 Yep. But mines running at 287MHz. (It was 200, but I had a play ;-) )

>
> > Now I'm converting it over to the PC, compiling it with
> > djgpp. I've got code to change to the screen mode I want
> > (640 by 480 in 32 bit) but I can't get the screen address to
> > write to. On the Acorn you just get the screen address and
> > start writing to it. I can't beleive that you need the pages
> > and pages of code I'm told I need. Ploting to screen is
> > simple; how can it be so hard on the PC?
>
> The PC is a patched together system. Memory is all over
> the place. VGA video memory used to be at absolute
> address 0x000A0000 (formerly known as A000:0000);
> SVGA card makers independently placed it at various
> positions and folded it in weird ways to fit into the address
> space of the PC; now VESA provides a way to get at the
> memory.

 Erk. I hope this memory mess problem gets sorted out. I knew it was
bad, but the more I find out the worse it is. I think a new type of
computer is needed. That would get rid of the memory poblem and finally
mean freedom from the x86 chips.

>
> > There must be a way of getting the screen address,
> > unlocking it from it's protection, and get on with the bloody
> > thing. My question is how? How can I get just the screen
> > address and unprotect it for use?
>
> Allegro, a driver library by Shawn Hargreaves et al.,
> can access VESA 2. Get the source at
> http://www.talula.demon.co.uk/allegro/
> Look at Allegro; then come back to C.O.M.D

 I'll study it carefully.

--
Catch ya later

JAB


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