Path: utzoo!mnetor!uunet!husc6!bbn!uwmcsd1!csd4.milw.wisc.edu!zdenko
From: zdenko@csd4.milw.wisc.edu (Zdenko Tomasic)
Newsgroups: comp.arch
Subject: Re: FORTRAN Horror
Message-ID: <5330@uwmcsd1.UUCP>
Date: 23 Mar 88 04:31:45 GMT
References: <24861@yale-celray.yale.UUCP> <1135@pembina.UUCP> <2424@saturn.ucsc.edu> <25461@yale-celray.yale.UUCP> <10037@steinmetz.steinmetz.ge.com> <6328@ames.arpa>
Sender: daemon@uwmcsd1.UUCP
Reply-To: zdenko@csd4.milw.wisc.edu (Zdenko Tomasic)
Organization: University of Wisconsin-Milwaukee
Lines: 55
Keywords: arithmetic IF, FORTRAN

In article <6328@ames.arpa> eugene@pioneer.UUCP (Eugene N. Miya) writes:
>In article <10037@steinmetz.steinmetz.ge.com> davidsen@crdos1.UUCP (bill davidsen) writes:
>>  The arithmetic if is one of the few good things in FORTRAN,
>
>Arithmetic is FORTRAN is an abortion!  No numerical analyst worth his (her)
                             ^^^^^^^^
				     shades of the Supreme Court decision,
				     any verdict on ADATRAN ? :-)

>salt would truncate or specify user specified rounding (See the SIGPLAN
>paper entitled Benchmark Semantics a month ago).  This is one of the reasons
>for the IEEE Floating Point Standard.  These are kludges and other short cuts
              ^^^^^^^^^^^^^^
>from the days when good floating point rounding "cost more."
                         ^^^^^^^^^^^^^^

The arithmetic IF is not restricted to floating point, its is fine
for integers. However you are right about FP, it is definitely very
IFFY there.

For very few cases arithmetic IF might be handy (i.e. all 3 branches
are different), but in most cases it is awkward since it forces at
least 2 labels to be used and gives a solid chance of writing a
dead code.  (It is a lot of fun to confuse a code reader, he/she
has really nothing better to do or be amused with :-)). The first
label following IF is really unnecessary if you believe in top-down
approach, but the syntax mandates it. It is certainly very baroque,
but how much code will break without it? (don't answer that!).

>
>From the Rock of Ages Home for Retired Hackers:
>
>--eugene miya, NASA Ames Research Center, eugene@ames-aurora.ARPA
>  "You trust the `reply' command with all those different mailers out there?"
>  "Send mail, avoid follow-ups.  If enough, I'll summarize."
>  {uunet,hplabs,hao,ihnp4,decwrl,allegra,tektronix}!ames!aurora!eugene

This discussion is extremely architectually relevant (IBM 70? :)),
anybody working on arithmetic if machine? (very IFFy indeed).

Zdenko Tomasic
UWM, Chem. Dept.
Milwaukee,WI,53201
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UUCP: ihnp4!uwmcsd1!csd4.milw.wisc.edu!zdenko
ARPA: zdenko@csd4.milw.wisc.edu
__________________________________________________________

Zdenko Tomasic
UWM, Chem. Dept.
Milwaukee,WI,53201
__________________________________________________________
UUCP: ihnp4!uwmcsd1!csd4.milw.wisc.edu!zdenko
ARPA: zdenko@csd4.milw.wisc.edu
__________________________________________________________