sysdeps/ieee754/dbl-64/s_fpclassify.c

   1 /* Return classification value corresponding to argument.
   2    Copyright (C) 1997-2016 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, see
  18    <http://www.gnu.org/licenses/>.  */
  19
  20 #include <math.h>
  21
  22 #include <math_private.h>
  23
  24
  25 int
  26 __fpclassify (double x)
  27 {
  28   u_int32_t hx, lx;
  29   int retval = FP_NORMAL;
  30
  31   EXTRACT_WORDS (hx, lx, x);
  32   lx |= hx & 0xfffff;
  33   hx &= 0x7ff00000;
  34   if ((hx | lx) == 0)
  35     retval = FP_ZERO;
  36   else if (hx == 0)
  37     retval = FP_SUBNORMAL;
  38   else if (hx == 0x7ff00000)
  39     retval = lx != 0 ? FP_NAN : FP_INFINITE;
  40
  41   return retval;
  42 }
  43 libm_hidden_def (__fpclassify)