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To: Marco Koegler <koegler AT mailhost DOT uni-koblenz DOT de>, djgpp AT delorie DOT com
From: Nate Eldredge <nate AT cartsys DOT com>
Subject: Re: Vesa LFB under DJGPP ... NEAR or FAR
Date: Thu, 23 Apr 1998 20:51:08 -0700
Message-ID: <19980424035042.AAK8293@ppp125.cartsys.com>
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At 10:37  4/23/1998 +0200, Marco Koegler wrote:
>Hi all!
>
>
>OK, here's my little problem. I want to code some VESA routines for the
>LFB modes. I'm currently at the following stage:
>
>I can set the mode I want and draw around on the screen, blah blah blah
>
>Very exciting indeed, but what I'm wondering is what approach to use for
>my screen pointer. Should I use NEAR pointers or FAR? I think NEAR
>pointers are VERY convinient to use, but what about memory protection?

They are convenient, but also dangerous. With them, you lose most of the
benefits of protected mode. Bugs in your code are perfectly free to wipe out
the OS or do other unpleasant things.

If you use a decent buffering algorithm with your graphics, far pointers are
not significantly slower.

>Well, if someone has done something similar to this I'd appreciate some
>suggestions.
>
>Thanks,
>
>Marco Koegler
>koegler AT uni-koblenz DOT de
>

Nate Eldredge
nate AT cartsys DOT com