Xref: utzoo comp.lang.c:16719 comp.lang.fortran:1799
Path: utzoo!attcan!uunet!seismo!esosun!ethan
From: ethan@esosun.UUCP (Ethan Brown)
Newsgroups: comp.lang.c,comp.lang.fortran
Subject: Re: Sun FPU question
Message-ID: <331@kvasir.esosun.UUCP>
Date: 4 Mar 89 22:22:48 GMT
References: <10660@pasteur.Berkeley.EDU>
Organization: SAIC, San Diego
Lines: 31
In-reply-to: faustus@dogwood.Berkeley.EDU's message of 3 Mar 89 22:58:15 GMT


In article <10660@pasteur.Berkeley.EDU> faustus@dogwood.Berkeley.EDU (Wayne A. Christopher) writes:

   Path: esosun!seismo!uunet!lll-winken!ncis.llnl.gov!helios.ee.lbl.gov!pasteur!dogwood.Berkeley.EDU!faustus
   From: faustus@dogwood.Berkeley.EDU (Wayne A. Christopher)
   Newsgroups: comp.lang.c
   Date: 3 Mar 89 22:58:15 GMT
   Sender: news@pasteur.Berkeley.EDU
   Lines: 6

   It seems that on some Suns, the FPU by default doesn't signal
   divide-by-zero errors, but makes the result Inf or NaN.  Is there a way
   to make it give a floating point error?  Does gcc have a flag for
   this?  How about the MIPS compiler, which has the same behavior?

	   Wayne

Wayne:
  I found similar problems on a Sun 4 when testing a FORTRAN program I'm
currently working on.  After the program terminated (normally, by the
way) I got some warnings about IEEE exceptions raised but not cleared.
It seems that only SOME of the IEEE exceptions cause program
termination.

  There are some manual sections explaining how to set up your own
IEEE exception handler (c.f. f77_ieee_environment.3f (there is probably
an equivalent entry for C)) that were very helpful.  After becoming familiar
with the IEEE exception handling functions you should be able to trap
your divide-by-zero conditions.

Hope this helps,