Path: utzoo!attcan!uunet!seismo!sundc!pitstop!sun!chiba!khb
From: khb%chiba@Sun.COM (Keith Bierman - Sun Tactical Engineering)
Newsgroups: comp.lang.fortran
Subject: Re: CDC FORTRAN trivia questions
Keywords: arithmetic if logical
Message-ID: <76273@sun.uucp>
Date: 4 Nov 88 21:30:17 GMT
References: <1196@helios.ee.lbl.gov> <3616@s.cc.purdue.edu> <7523@ut-emx.UUCP> <3622@s.cc.purdue.edu> <7693@boring.cwi.nl> <3627@s.cc.purdue.edu> <2183@tekcae.CAX.TEK.COM>
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Reply-To: khb@sun.UUCP (Keith Bierman - Sun Tactical Engineering)
Organization: Sun Microsystems, Mountain View
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In article <2183@tekcae.CAX.TEK.COM> kurtk@tekcae.CAX.TEK.COM (Kurt Krueger) writes:
>Something that may be confusing the issue is that CDC in the FTN and FTN5
>compilers always inserted code to make sure that -0 would 'disappear'.
>In logical statements, this would at times amount to adding a +0 to the
>logical expression so SOME mathematics would always get done BEFORE a sign
>test was done.  The hardware is such that -0 can NEVER get calculated
>but is a perfectly legitimate operand.

-0 DID get computed. This proved to be a problem during my student
days on a Cyber 17x with using the ETH Pascal compiler in conjuction
with one of the fortran compilers (I forget which) Pascal couldn't
cope with -0's which were being generated by the fortran compiler.






Keith H. Bierman
It's Not My Fault ---- I Voted for Bill & Opus