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Mail Archives: djgpp/1996/10/15/02:53:55

Date: Tue, 15 Oct 1996 08:30:17 +0200 (IST)
From: Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
To: Emil0 AT aol DOT com
Cc: djgpp AT delorie DOT com
Subject: Re: Another way to access VGA memory
In-Reply-To: <961014170302_333643612@emout14.mail.aol.com>
Message-Id: <Pine.SUN.3.91.961015082852.19543A-100000@is>
Mime-Version: 1.0

On Mon, 14 Oct 1996 Emil0 AT aol DOT com wrote:

> At first this method might seem to be a "hack" - the documentation says this
> function should be "used sparingly". It is however in the DPMI specs, and so
> is guaranteed to be in all future DPMI versions (I think...). It's worked on

This is what the DPMI Spec says on this function:

                 o    Descriptors created  by this function should never
                      be modified or freed.  For this reason, you should
                      use this  function sparingly.    If  your  program
                      needs to examine various real mode addresses using
                      the same selector you should allocate a descriptor
                      and change  the base  using the  Set Segment  Base
                      Address function instead of using this function.
                 o    The descriptor's limit will be set to 64K.
                 o    The intent  of this  function is to allow programs
                      easy access  to commonly  used real  mode segments
                      such as 40h and A000h.  Do not use this service to
                      obtain descriptors to private data areas.


So in this case, it seems to be safe to use this service.

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