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From: "thenlich at users dot sourceforge.net" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug fortran/49010] New: Result of MOD and MODULO intrinsic has wrong sign
Date: Mon, 16 May 2011 09:00:00 -0000	[thread overview]
Message-ID: <bug-49010-4@http.gcc.gnu.org/bugzilla/> (raw)

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49010

           Summary: Result of MOD and MODULO intrinsic has wrong sign
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: thenlich@users.sourceforge.net


If the first argument to the MOD and MODULO intrinsic is negative, and the
magnitude of the result is zero, the function returns a negative zero.

Fortran 2003/2008:
MOD: The value of the result is A − INT (A/P) * P.
MODULO: The value of the result is A − FLOOR (A / P) * P.

The values returned by these intrinsics should be the same as the expressions
by which the functions are defined; which is zero, without a negative sign.

Example:
program test_mod
    real :: a, p

    a = -4.0
    p = 2.0
    print *, mod(a, p), a - int(a / p) * p ! -0 0 expected 0 0
    print *, modulo(a, p), a - floor(a / p) * p ! -0 0 expected 0 0
end program test_mod


             reply	other threads:[~2011-05-16  8:26 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-05-16  9:00 thenlich at users dot sourceforge.net [this message]
2011-05-16 10:49 ` [Bug fortran/49010] " burnus at gcc dot gnu.org
2011-05-16 21:03 ` kargl at gcc dot gnu.org
2011-05-16 21:29 ` sgk at troutmask dot apl.washington.edu
2011-05-16 22:24 ` sgk at troutmask dot apl.washington.edu
2011-05-17  7:40 ` thenlich at users dot sourceforge.net
2011-05-17 10:18 ` jb at gcc dot gnu.org
2011-05-17 12:30 ` thenlich at users dot sourceforge.net
2011-05-17 14:34 ` jb at gcc dot gnu.org
2011-05-17 14:48 ` sgk at troutmask dot apl.washington.edu
2011-05-17 15:15 ` sgk at troutmask dot apl.washington.edu
2011-05-17 16:36 ` jb at gcc dot gnu.org
2012-05-05  8:00 ` jb at gcc dot gnu.org
2012-05-05  8:17 ` jb at gcc dot gnu.org

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