Date: Sun, 23 Apr 1995 09:24:34 +0300
From: eliz AT is DOT elta DOT co DOT il. (Eli Zaretskii)
To: KM5M AT C53000 DOT PETROBRAS DOT ANRJ DOT BR
Subject: Re: DJGPP
Cc: djgpp AT sun DOT soe DOT clarkson DOT edu

> Recently I bougth DJGPP C Compiler but I have a doubt about how to access
> MS-DOS's conventional memory space when I am running a program in protected
> mode, under MS-DOS.
> Basicaly, I would like to access the Video RAM memory addresses (0xb8000).
> When I am programing in 16bit code in real mode, I can access directly
> this address like this:
>  .....
> Now, How can I declare a 32bit linear memory pointer to point to the
> 0xb8000 MS-DOS's conventional address and assign a value to it in
> DJGPP sintax?

The full DJGPP archive includes a file named faqNNN.zip (where NNN is
the version number).  This is the DJGPP FAQ list, which in Chapter 18
discusses the issues that puzzle you.  If the package you got doesn't
include this file (btw, why should one buy free software?), then look
on your nearest SimTel mirror, in the msdos/djgpp directory.

> I would like to get the source of the dosmemget() and dosmemput()
> functions. Where can I get them?

Look inside djlsr112.zip, file libsrc/c/dos/dosmem.s.