math/w_ilogb.c

   1 /* Copyright (C) 2012 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Adhemerval Zanella <azanella@linux.vnet.ibm.com>, 2011.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <math.h>
  20 #include <errno.h>
  21 #include <math_private.h>
  22
  23 /* wrapper ilogb */
  24 int
  25 __ilogb (double x)
  26 {
  27   int r = __ieee754_ilogb (x);
  28   if (__builtin_expect (r == FP_ILOGB0, 0)
  29       || __builtin_expect (r == FP_ILOGBNAN, 0)
  30       || __builtin_expect (r == INT_MAX, 0))
  31     {
  32       __set_errno (EDOM);
  33       feraiseexcept (FE_INVALID);
  34     }
  35   return r;
  36 }
  37
  38 weak_alias (__ilogb, ilogb)
  39 #ifdef NO_LONG_DOUBLE
  40 strong_alias (__ilogb, __ilogbl)
  41 weak_alias (__ilogb, ilogbl)
  42 #endif