Date: Fri, 17 May 2002 09:01:11 +0200 (CEST) From: Andreas Haakh <ah@alvman.Haakh.de> To: FreeBSD-gnats-submit@FreeBSD.org Subject: kern/38170: fpgetmask, fpsetmask yield strange results Message-ID: <200205170701.g4H71BVv000804@alvman.Haakh.de>
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>Number: 38170
>Category: kern
>Synopsis: fpgetmask, fpsetmask yield strange results
>Confidential: no
>Severity: serious
>Priority: medium
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Fri May 17 00:10:01 PDT 2002
>Closed-Date:
>Last-Modified:
>Originator: Andreas Haakh
>Release: FreeBSD 4.6-RC i386
>Organization:
Ingenieurbüro für Baustatik
>Environment:
System: FreeBSD alvman.Haakh.de 4.6-RC FreeBSD 4.6-RC #0: Fri May 17 07:18:23 CEST 2002 root@alvman.Haakh.de:/usr/obj/usr/src/sys/ALVMAN i386 i686-class CPU
>Description:
I tried to modify the default fp_exception-mask. The results from fpgetmask and fpsetmask (and probably some other fp[sg]et-routines) are buggy.
>How-To-Repeat:
The following codeexample shows this strange behaviour:
#include <stdio.h>
#include <ieeefp.h>
int main (void) {
fp_except_t except, res;
res=fpgetmask();
printf ("fp_except from fpgetmask: \t0x%02x!\n", res);
except = FP_X_INV|FP_X_DZ|FP_X_OFL|FP_X_STK;
printf ("attempt to set fp_except to: \t0x%02x!\n", except);
res=fpsetmask(except);
printf ("fp_except from fpsetmask: \t0x%02x!\n", res);
res=fpgetmask();
printf ("fp_except from fpgetmask: \t0x%02x!\n", res);
res=fpsetmask(except);
printf ("retry to set fp_except to:\t0x%02x!\n", except);
res=fpsetmask(except);
printf ("fp_except from fpsetmask: \t0x%02x!\n", res);
res=fpgetmask();
printf ("fp_except from fpgetmask: \t0x%02x!\n", res);
exit (except);
}
The results from this prog are:
fp_except from fpgetmask: 0x00!
attempt to set fp_except to: 0x4d!
fp_except from fpsetmask: 0x3f!
fp_except from fpgetmask: 0x0d!
retry to set fp_except to: 0x4d!
fp_except from fpsetmask: 0x32!
fp_except from fpgetmask: 0x0d!
>Fix:
correct the inline functions and/or macros in <machine/floatingpoint.h>
I have not enough knowledge to do it myself...
>Release-Note:
>Audit-Trail:
>Unformatted:
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