Xref:	news2.mv.net comp.os.msdos.djgpp:4812
From:	Shawn Hargreaves <slh100 AT york DOT ac DOT uk>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: remapping the vga
Date:	Mon, 10 Jun 1996 19:03:58 +0100
Organization:	The University of York, UK
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Message-ID:	<Pine.SGI.3.91.960610190014.14166A-100000@tower.york.ac.uk>
NNTP-Posting-Host:	tower.york.ac.uk
Mime-Version:	1.0
In-Reply-To:	<31BC39F0.65A@unm.edu>
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

> is there any other way to map 64k of memory to 0xa0000 without using
> __djgpp_map_physical_memory?  im wondering because the only way this 
> works is if the program runs with cwsdpmi, and not under windows cuz its 
> not dpmi 1.0.  or is it possible to 'force' a program to use cwsdpmi 
> even if it is under windows?

No, there is no other way to remap it, and no, you can't force cwsdpmi 
under windows. Even under DOS that is a dangerous remapping to do: you 
could maybe tell the OS to map 0xa0000 to the video hardware, but what 
happens if the linker has located some essential bit of your program in 
that address range? I don't think there is any way to tell djgpp's malloc() 
not to use that bit of memory either. To write to video memory, you 
really should use either far pointers or the fat DS trick. I don't see 
any problem with either of those methods...


/*
 *	Shawn Hargreaves.        Why is 'phonetic' spelt with a ph?
 *	Check out Allegro and FED on http://www.york.ac.uk/~slh100/
 */

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