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From: mellon@mit-prep.ARPA (Ted Lemonmellon/.name)
Newsgroups: net.unix,net.micro,net.micro.pc
Subject: Re: Physical memory access under Xenix
Message-ID: <27@mit-prep.ARPA>
Date: Wed, 7-May-86 13:48:40 EDT
Article-I.D.: mit-prep.27
Posted: Wed May  7 13:48:40 1986
Date-Received: Fri, 9-May-86 10:22:03 EDT
Organization: The MIT AI Lab, Cambridge, MA
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Xref: watmath net.unix:7799 net.micro:14554 net.micro.pc:8102


> Yup, there are two system calls dscralloc() which allocates a descriptor
> for you and mmudescr() which points it at a physical address. If you
> have far keywords enabled you can do something like 

First of all, thanks for responding.   I received some really good
suggestions, of which the above was the cleanest.   Unfortunately, the
IBM version of Xenix does not have a symbol _dscralloc(), while the
SCO version does.   Does anybody know if there is an equivalent
function in the IBM version of Xenix, or do I need to use John
Little's method of hacking a (hopefully) unused entry in the GDT?

When this is over and I have made a driver for IBM Xenix and SCO
Xenix, I will post a summary of how I did it...   For now, I am going
to hack the GDT...

			       _MelloN_-- 
Ted Lemon
Project GNU of the Free Software Foundation

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