Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!cornell!calvin!johns
From: johns@calvin.EE.CORNELL.EDU (John Sahr)
Newsgroups: comp.sys.dec
Subject: how to make div-by-zero cause a fatal error on DS3100?
Keywords: DECstation 3100, SIGFPE, floating point error
Message-ID: <1133@calvin.EE.CORNELL.EDU>
Date: 21 Jun 89 18:27:32 GMT
Distribution: comp
Organization: Cornell Space Plasma Physics, Ithaca, NY
Lines: 19

We have several DS3100's in our group, being used for a variety of things,
including numbercrunching.  The desired behaviour for floating point
errors is a fatal error (for our purposes), which is exactly what happens
on our microvaxes and one other Unix machine.

The DS3100's fortran and C compilers produce code which does not seem to
generate either fatal errors (unheeded SIGFPE) or any other signals, but
just starts to propagate NaN's and Infinity's, and slows down _dramatically_.

Is there a way to detect floating point errors through any kind of signal?
What are we doing wrong?  Compiler flags? GCC?

	thanks, 
	john


-- 
John Sahr,     Dept. of Electrical Eng., Cornell University, Ithaca, NY 14853
johns@{alfven,calvin}.ee.cornell.edu,  {rochester,cmcl2}!cornell!calvin!johns