Date: Thu, 4 Mar 1999 17:48:25 -0500 (EST) From: "Crist J. Clark" <cjc@cc942873-a.ewndsr1.nj.home.com> To: freebsd-hackers@freebsd.org Subject: FP Math Problem Message-ID: <199903042248.RAA08114@cc942873-a.ewndsr1.nj.home.com>
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I am trying to figure out why the following program produces a
floating point exception and core dumps.
#include <stdio.h>
#include <floatingpoint.h>
#include <float.h>
int main()
{
double a = 1e200;
double b;
printf("fpgetmask: %o\n",fpgetmask());
printf("a: %e\n",a);
b = a*a;
printf("isinf: %d\n",isinf(b));
printf("isnan: %d\n",isnan(b));
printf("b > DBL_MAX: %d\n",b>DBL_MAX);
printf("b: %e\n",b);
return 0;
}
My output is,
[112:~/tmp] ./dtest
fpgetmask: 15
a: 1.000000e+200
isinf: 0
isnan: 0
Floating exception (core dumped)
I started with this on -questions and (although the thread got
sidetracked by a bad test program I presented at the beginning) other
FreeBSDers have not reproduced the error, but get what I would expect,
% ./dtest
fpgetmask: 15
a: 1.000000e+200
isinf: 1
isnan: 0
b > DBL_MAX: 1
b: inf
However, I get the FPE and core dump on my three FreeBSD machines
(different hardware on each). All are,
FreeBSD pc252.scitec.com 2.2.8-STABLE FreeBSD 2.2.8-STABLE #0: Mon Mar 1 14:25:39 EST 1999
Give or take a few days on the CVSup. (All were recently built to
2.2.8-S from 2.2.7-R.)
It has been suggested I have somehow mucked up my floating point,
but I do not know where to start and -questions did not
produce many leads.
Thanks for any help. More details can be provided; I would not know
where to start.
--
Crist J. Clark cjclark@home.com
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