libm/s_fpclassify.c

   1 /* Return classification value corresponding to argument.
   2    Copyright (C) 1997, 2002 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 int __fpclassify(double x)
  25 {
  26   u_int32_t hx, lx;
  27   int retval = FP_NORMAL;
  28
  29   EXTRACT_WORDS (hx, lx, x);
  30   lx |= hx & 0xfffff;
  31   hx &= 0x7ff00000;
  32   if ((hx | lx) == 0)
  33     retval = FP_ZERO;
  34   else if (hx == 0)
  35     retval = FP_SUBNORMAL;
  36   else if (hx == 0x7ff00000)
  37     retval = lx != 0 ? FP_NAN : FP_INFINITE;
  38
  39   return retval;
  40 }
  41 libm_hidden_def(__fpclassify)