pjh@mccc.edu (Peter J. Holsberg) (04/18/91)
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
daw@cbnewsh.att.com (David Wolverton) (04/20/91)
In article <1991Apr18.144759.4492@mccc.edu>, pjh@mccc.edu (Peter J. Holsberg) writes: > Here's the source: [lots deleted] If your system is using IEEE 754-based floating point (which has a good probability of being true), then it is possible to ask the floating point subsystem to signal several types of f.p. exceptions, including "inexact" (that is, that a computation had to round off a result). Normally, you would never want to enable this particular signal, but if it was enabled, it would probably fire on ANY call to exp(), because it would be very unlikely that exp()'s internal computations would be completely roundoff-free. Dave Wolverton daw@honshu.att.com
jfv@cbnewsk.att.com (j.f.van valkenburg) (04/22/91)
In article <1991Apr18.144759.4492@mccc.edu>, pjh@mccc.edu (Peter J. Holsberg) writes: > 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 > various messages I tried it on my 3B2/1000 running SVR3.2.2 and it complied with no burps and ran smooth I compiled cc foo.c -lm -o foo result was Exp(0) = 1.000000 Exp(1) = 2.718282 Exp(-1) = 0.367879 I don't know what happened but, I had no trouble. ------------------------ James F. Van Valkenburg a.k.a. "van" AT&T Attmail: !jfv jfv@cbnewsk.att.com Atlanta, GA. Voice 404-873-7920 =============================================================================== ---- Standard Disclaimers included -- Just another grunt at AT&T ---- ===============================================================================
pjh@mccc.edu (Pete Holsberg) (04/24/91)
In article <1991Apr22.164400.20859@cbnewsk.att.com> jfv@cbnewsk.att.com (j.f.van valkenburg) writes:
=
=I tried it on my 3B2/1000 running SVR3.2.2
=
=and it complied with no burps and ran smooth
I should point out that everyone else who has tried it has not had the
problem, but that no one has exactly the same software I have. Please,
if you have AT&T UNIX SV/386 R3.2.2 and SCDE 5.0/3, try the program and
let me know what happens.
If you have a different R3.2.x and/or a different SCDE, please try it,
too. Incidentally, the "S" in "SCDE" stands for "Standard" as in "ANSI."
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