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From: brent@cadovax.UUCP (Brent Rector)
Newsgroups: net.lang.c
Subject: Re: register variables
Message-ID: <686@cadovax.UUCP>
Date: Tue, 2-Jul-85 15:47:52 EDT
Article-I.D.: cadovax.686
Posted: Tue Jul  2 15:47:52 1985
Date-Received: Sun, 7-Jul-85 06:10:44 EDT
References: <472@crystal.UUCP> <365@umcp-cs.UUCP> <421@osu-eddie.UUCP>
Reply-To: brent@cadovax.UUCP (Brent Rector)
Distribution: net
Organization: Contel Cado, Torrance, CA
Lines: 21

In article <421@osu-eddie.UUCP> pritch@osu-eddie.UUCP (Norman Pritchett) writes:
>Just for the sake of information, VMS ignores register declarations and
>automatically decides for itself how frequently you use each variable and
>whether or not to make it a "register declaration".  I personally don't
>think this is the wisest approach but after looking at a number of machine
>code listings it actually appears to work well under most conditions.
>
>Norm Pritchett
>UUCP:   cbosgd!osu-eddie!pritch

So what happens then if you are frequently referencing a memory mapped
device register, will the VMS compiler cache the first reference in a
register?  (Note that I am aware of the proposed 'volatile' definition
in the standard).  Or can you tell the compiler to listen to register
definitions in certain cases.

-- 
--------------------------------------------------------------
Brent E. Rector - CONTEL CADO, Torrance, CA
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