From: Charles Sandmann <sandmann AT new-orleans DOT NeoSoft DOT com>
Subject: Re: Accessing absolute addresses in memory (>1M) and ports.
To: sparre AT connect DOT nbi DOT dk (Jacob Sparre Andersen)
Date: Fri, 6 Jan 1995 18:38:47 -0600 (CST)
Cc: djgpp AT sun DOT soe DOT clarkson DOT edu

> Is it possible (and how?) to access ports and absolute addresses in 
> memory (above 1M) with GNAT/DJGPP?

ports can be accessed via inline assembler or via routines in pc.h

Absolute addresses can be addressed under DPMI providers by using 
DPMI call 0x0800, and the farptr.h functions.  (BTW, this is 
supported in the free DPMI and will be the *ONLY* way to access 
physical memory locations > 1Mb in V2).

Under non-DPMI providers, add 0xe0000000 to the physical address
and use that as a pointer.  Note, this feature disappears in V2.

If you want to write to a single API and don't have DPMI, I can
let you have an early release of the free DPMI to use with V1.12