Xref: utzoo comp.compilers:1436 comp.lang.fortran:3997
Path: utzoo!attcan!uunet!bu.edu!husc6!spdcc!esegue!compilers-sender
From: henry@zoo.toronto.edu (Henry Spencer)
Newsgroups: comp.compilers,comp.lang.fortran
Subject: Re: IEEE 754 vs Fortran arithmetic
Keywords: Fortran
Message-ID: <1990Oct24.162529.20452@zoo.toronto.edu>
Date: 24 Oct 90 16:25:29 GMT
References: <9010230628.AA22160@admin.ogi.edu>
Sender: compilers-sender@esegue.segue.boston.ma.us
Reply-To: henry@zoo.toronto.edu (Henry Spencer)
Organization: U of Toronto Zoology
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Approved: compilers@esegue.segue.boston.ma.us

> [our moderator writes]
>... I know of no reason that an IEEE implementation of F77 would be
>nonconforming. ...

I can think of at least one:  F77 flatly denies the existence of -0,
while IEEE demands it.  (One of Dr. Kahan's favorite examples in his
talks is an algorithm which, when implemented straightforwardly, does
the right thing if -0 is implemented properly and screws up bizarrely
if not, so yes, it does matter.)
-- 
Henry Spencer at U of Toronto Zoology, henry@zoo.toronto.edu   utzoo!henry
[Given that +0 = -0, it's not clear to me that the existence of -0 breaks
anything.  Keep in mind that F77 is a permissive standard, extensions are
permitted so long as conforming programs do the right thing. -John]
-- 
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