math/w_llogb_template.c

   1 /* Wrapper to implement llogb in terms of ilogb.
   2    Copyright (C) 2012-2017 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   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 <limits.h>
  22 #include <math_private.h>
  23
  24 long int
  25 M_DECL_FUNC (__llogb) (FLOAT x)
  26 {
  27   int r = M_SUF (__ieee754_ilogb) (x);
  28   long int lr = r;
  29   if (__glibc_unlikely (r == FP_ILOGB0)
  30       || __glibc_unlikely (r == FP_ILOGBNAN)
  31       || __glibc_unlikely (r == INT_MAX))
  32     {
  33 #if LONG_MAX != INT_MAX
  34       if (r == FP_ILOGB0)
  35         lr = FP_LLOGB0;
  36       else if (r == FP_ILOGBNAN)
  37         lr = FP_LLOGBNAN;
  38       else
  39         lr = LONG_MAX;
  40 #endif
  41       __set_errno (EDOM);
  42       __feraiseexcept (FE_INVALID);
  43     }
  44   return lr;
  45 }
  46 declare_mgen_alias (__llogb, llogb)