Xref: utzoo comp.sys.att:12162 comp.lang.c:38469
Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!pacific.mps.ohio-state.edu!linac!att!princeton!njsmu!mccc!pjh
From: pjh@mccc.edu (Peter J. Holsberg)
Newsgroups: comp.sys.att,comp.lang.c
Subject: Strange Behavior -- AT&T Std C
Message-ID: <1991Apr18.144759.4492@mccc.edu>
Date: 18 Apr 91 14:47:59 GMT
Organization: The College On The Other Side of Route One
Lines: 71

Here's the source:

#include <stdio.h>
#include <math.h>
void main()
{
	printf("Exp(0) = %f\n", exp(0.0));
	printf("Exp(1) = %f\n", exp(1.0));
	printf("Exp(-1) = %f\n", exp(-1.0));
}


Here's a typescript of the compilation, execution, and debugging runs:

Script is typescript, started Thu Apr 18 10:41:28 1991

mccc [pjh] /usr/pjh/c> cc -g -o y y.c -lm

mccc [pjh] /usr/pjh/c> y
Floating exception(coredump)

mccc [pjh] /usr/pjh/c> sdb y
no source file				WHY DOES SDB SAY THIS????
0x2cc 	(exp+368:)	   ffree  %st(5)	[ %st(5) ]
*r
./y 
SIGNALED 8 process 4444
0x2cc 	(exp+368:)	   ffree  %st(5)	[ %st(5) ]
*s
SIGNALED 8 process 4444
0x2ce 	(exp+370:)	   popl   %edi	[ %edi ]
*s
STEPPED process 4444 function main() in y.c
6:		printf("Exp(1) = %f\n", exp(1.0));
*s
STEPPED process 4444 function main() in y.c
7:		printf("Exp(-1) = %f\n", exp(-1.0));
*s
SIGNALED 8 process 4444
0x2ce 	(exp+370:)	   popl   %edi	[ %edi ]
*s
STEPPED process 4444 function main() in y.c
7:		printf("Exp(-1) = %f\n", exp(-1.0));
*s
STEPPED process 4444 function main() in y.c
8:	}
*s
Exp(0) = 1.000000
Exp(1) = 2.718282
Exp(-1) = 0.367879		GOOD LORD!  IT DID THE CALCULATIONS!!
Process 4444 has terminated.
*s
Can't step process, it's a core file.
*q
mccc [pjh] /usr/pjh/c>

Script done Thu Apr 18 10:42:23 1991

This was done, incidentally, both with the original libm.a (that I was
*so* sure was buggy!) and a borrowed copy of a later version of libm.a!!

What on earth can be causing the "Floating exception(coredump)"????

Thanks,
Pete

-- 
Prof. Peter J. Holsberg      Mercer County Community College
Voice: 609-586-4800          Engineering Technology, Computers and Math
UUCP:...!princeton!mccc!pjh  1200 Old Trenton Road, Trenton, NJ 08690
Internet: pjh@mccc.edu	     Trenton Computer Festival -- 4/20-21/91