Date: Tue, 3 Mar 1998 10:48:14 +0200 (IST)
From: Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
To: Doug Otis <dotis AT aponet DOT com>
cc: djgpp AT delorie DOT com
Subject: Re: Is there a function to convert a pointer to its physical location?
In-Reply-To: <34FB87F1.2BD0A6AC@aponet.com>
Message-ID: <Pine.SUN.3.91.980303104302.3192A-100000@is>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
Precedence: bulk


On Mon, 2 Mar 1998, Doug Otis wrote:

> Does anyone have a DPMI interface
> that does not use the MMU so that the translation would be just base +
> offset?

AFAIK, this is impossible: protected mode always uses the MMU.

> Is there a function that has access to the Page Directory and
> Page Table to perform the translation under DJGPP?

I'm not sure, but even if it is possible, you will need to run under a
ring-zero DPMI server, such as CWSDPR0, which allows to use priviledged
instructions that access the page directory and associated data
structures.  Using CWSDPR0 means you don't have virtual memory. 

> At first blush, it
> seems possible to disable paging if only one program (DOS) uses the VM
> mode.

I'm not sure I follow you.  What does paging have to do with logical-to-
physical address translation?