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From: BREEBAAR%HLERUL5.BITNET@wiscvm.wisc.EDU
Newsgroups: comp.lang.c
Subject: Absolute addressing in Turbo-C
Message-ID: <8766@brl-adm.ARPA>
Date: Wed, 12-Aug-87 14:31:05 EDT
Article-I.D.: brl-adm.8766
Posted: Wed Aug 12 14:31:05 1987
Date-Received: Sat, 15-Aug-87 00:51:53 EDT
Sender: news@brl-adm.ARPA
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I am currently working on an IBM AT with a Professional Graphics Display,
and am trying to rewrite my Turbo Pascal routines for communicating with
the PG-Adaptor in C, a language in which I have some programming
experience, but am no expert in.
I have to use absolute addressing, because of various buffers and variables
that both the PGA and I need to access. To illustrate, some of the original
Turbo Pascal declarations:

  VAR  outBuffer : ARRAY [0..255] OF BYTE ABSOLUTE $C000:$6000;
       outHead   : BYTE ABSOLUTE $C000:$6300;
       outTail   : BYTE ABSOLUTE $C000:$6301;

My problem ofcourse is: how do I do this in C? (I am using Turbo-C,
but have no manual (yet).)
Firstly I would like to know if Turbo-C has something equivalent to the
'ABSOLUTE' keyword. Probably not.
So secondly, I'd like the proper C solution to this.
I have some vague ideas myself, involving the assigning of values to pointers
but am at a loss at how to implement them, especially with IBM addresses
being 20 bits long etc. etc.
Can anyone out there help me?
Thanx.

Leo Breebaart (BREEBAART@HLERUL5.BITNET)
University of Leiden
The Netherlands