Date: Thu, 27 Nov 1997 13:56:49 +0200 (IST)
From: Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
To: sbaeck AT bewoner DOT dma DOT be
cc: djgpp AT delorie DOT com
Subject: Re: 32-bit memory access
In-Reply-To: <347C812A.55C9@bewoner.dma.be>
Message-ID: <Pine.SUN.3.91.971127135158.5743Y-100000@is>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
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On Wed, 26 Nov 1997 sbaeck AT bewoner DOT dma DOT be wrote:

> For a project I am currently working on, I need to write
> DOS(!?)-software that can access the full 32-bit address-map of an Intel
> Pentium.  This is impossible in real mode (DOS), so I'm using the
> djgpp-compiler to compile my software to protected mode.  I know that I
> have to use DPMI and I know the DPMI-theory, but I don't know how to
> implement it using djgpp (and cwsdpmi).  Good documentation and
> example-source-code would be welcome.

You don't need to do anything.  DJGPP already does all of the low-level
DPMI stuff for you.  You can call `malloc' as in any C program and get all
the virtual memory that your system makes available.  Typical DOS/Windows
environments will allow up to 64MB of virtual memory.  To get more than
that, you will have to use plain DOS (no Windows) with CWSDPMI, which will
bring you to 196MB.  If you need still more, you can get as much as 256MB
if you have more than 64MB of physical memory installed and install a
memory manager (e.g. from DOS 7) that supports more than 64MB physical
RAM.