Date: Sun, 28 Aug 2005 17:59:06 GMT From: Chuck Ebbert <76306.1226@compuserve.com> To: freebsd-gnats-submit@FreeBSD.org Subject: i386/85417: Possible bug in ia32 floating-point exception handler Message-ID: <200508281759.j7SHx6Yo072283@www.freebsd.org> Resent-Message-ID: <200508281800.j7SI0VRX089224@freefall.freebsd.org>
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>Number: 85417
>Category: i386
>Synopsis: Possible bug in ia32 floating-point exception handler
>Confidential: no
>Severity: non-critical
>Priority: low
>Responsible: freebsd-i386
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Sun Aug 28 18:00:31 GMT 2005
>Closed-Date:
>Last-Modified:
>Originator: Chuck Ebbert
>Release: RELENG_6
>Organization:
>Environment:
>Description:
src/sys/i386/i386/trap.c 1.277.2.1 lines 303-308:
303: case T_ARITHTRAP: /* arithmetic trap */
304: #ifdef DEV_NPX
305: ucode = npxtrap();
306: if (ucode == -1)
307: goto userout;
308: #else
src/sys/i386/isa/npx.c:npxtrap()
can never return -1, so SIGFPE code 0 will be sent to the
user app if no unmasked i387 exception bits are set. This
can happen on some non-Intel processors.
>How-To-Repeat:
>Fix:
(1) If the current behavior is correct, remove the if statement
at line 306 since it has no effect and only confuses reviewers.
(2) Otherwise, change fpetable[] in src/sys/i386/isa/npx.c
so entry 0 is -1 instead of 0
>Release-Note:
>Audit-Trail:
>Unformatted:
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