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: unassig...@gcc.gnu.org
ReportedBy: thenl...@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
