Date:	Mon, 12 Aug 1996 12:42:35 +0200 (MET DST)
From:	Mark Habersack <grendel AT ananke DOT amu DOT edu DOT pl>
Reply-To:	grendel AT ananke DOT amu DOT edu DOT pl
To:	John Joseph Newbigin <079519 AT bud DOT cc DOT swin DOT edu DOT au>
cc:	djgpp AT delorie DOT com
Subject:	Re: Accessing graphics memory
In-Reply-To:	<Pine.OSF.3.91.960808131941.31475B-100000@bud.cc.swin.edu.au>
Message-ID:	<Pine.NEB.3.95.960812123923.15833D-100000@ananke.amu.edu.pl>
MIME-Version:	1.0

On Fri, 9 Aug 1996, John Joseph Newbigin wrote:

>I was thinking about the ways to access graphics video memory and it hit 
>me that it the video memory could be paged so that it is part of the data 
>segment then it can be accessed with a near pointer and still keep memory 
>protection.
>
>I have not tried any of the DPMI services in DJGPP so I don't know how 
>easy or hard this would be, or if it is possible at all, so I am 
>suggesting it here.  Does anyone know if this is possible and if so, how 
>to do it?
Well, I guess it might be accomplished using __dpmi_map_device_memory (maybe
it is not the exact name, but you'll recognise it ;-))). Note however that
this is a DPMI 1.0 call which is simulated by CWSDPMI, and might be not
supported (or rather IT IS NOT supported) by other 0.9 servers.
I'm not sure, however, whether it is possible to tailor the allocated buffer
to the default data seg of djgpp app.

Regards, Mark

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