Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 6/24/83; site cadovax.UUCP Path: utzoo!watmath!clyde!burl!ulysses!allegra!mit-eddie!genrad!decvax!decwrl!greipa!pesnta!pertec!scgvaxd!trwrb!trwrba!cadovax!brent 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 { decvax, hplabs, ihnp4, ucbvax, sdcrdcf }!trwrb!cadovax!brent philabs!cadovax!brent