Article View: comp.arch
Article #13434Re: Optimization vs. the programmer
From: rpw3
Date: Wed, 08 Apr 1987 03:12
Date: Wed, 08 Apr 1987 03:12
26 lines
1421 bytes
1421 bytes
In article <479@danews.ATT.COM> lvc@danews.ATT.COM (Larry Cipriani) writes:
+---------------
| There is a certain computer (that I still use) that requires the statement:
| n = n;
| in order to force the hardware to work right for certain values of n...
| If I had an optimizing compiler that was smart (?$!?) enough to excise this
| I couldn't make the machine work right.
+---------------
I can't agree. Instead, *tell* the compiler that you need to do this.
In ANSI C (or any useful optimizing C compiler), simply say:
volatile int n;
...
n = n;
And the compiler will *always* fetch & store "n" when referenced.
Rob Warnock
Systems Architecture Consultant
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Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: arc1-ca.pugleaf.net!utzoo!utgpu!water!watnot!watmath!clyde!cbatt!ucbvax!amdcad!rpw3 From: rpw3@amdcad.UUCP Newsgroups: comp.arch,comp.lang.c Subject: Re: Optimization vs. the programmer Message-ID: <16014@amdcad.AMD.COM> Date: Tue, 7-Apr-87 22:12:43 EST Article-I.D.: amdcad.16014 Posted: Tue Apr 7 22:12:43 1987 Date-Received: Sat, 11-Apr-87 03:34:45 EST References: <479@danews.ATT.COM> Reply-To: rpw3@amdcad.UUCP (Rob Warnock) Distribution: world Organization: [Consultant] San Mateo, CA Lines: 26 Summary: Use "volatile" when needed