From: sbaeck AT bewoner DOT dma DOT be
Newsgroups: comp.os.msdos.djgpp
Subject: Re: 32-bit memory access
Date: Thu, 27 Nov 1997 19:12:38 +0100
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Eli Zaretskii wrote:
> 
> 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.

Thanks a (VERY BIG) lot for your help, but I still have one problem : As
far
as I know, the malloc-function does not allow to select the base-adress
of the allocated memory-block and that is exactly what I need, because I
have
to access PCI-devices.  If you could provide me a solution to this
problem
(or just tell me where I might find it), you'd save me from a lot of
sleepless nights.

Since you seem to know a lot (more than me) about djgpp, ... can you
tell me
where I can find some good documentation on djgpp (on the net or a good
book).


Thanks again.