sysdeps/libm-ieee754/s_fpclassify.c

   1 /* Return classification value corresponding to argument.
   2    Copyright (C) 1997 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 Library General Public License as
   8    published by the Free Software Foundation; either version 2 of the
   9    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    Library General Public License for more details.
  15
  16    You should have received a copy of the GNU Library General Public
  17    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  18    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  19    Boston, MA 02111-1307, USA.  */
  20
  21 #include <math.h>
  22
  23 #include "math_private.h"
  24
  25
  26 int
  27 __fpclassify (double x)
  28 {
  29   u_int32_t hx, lx;
  30   int retval = FP_NORMAL;
  31
  32   GET_WORDS (hx, lx, x);
  33   lx |= hx & 0xfffff;
  34   hx &= 0x7ff00000;
  35   if ((hx | lx) == 0)
  36     retval = FP_ZERO;
  37   else if (hx == 0)
  38     retval = FP_SUBNORMAL;
  39   else if (hx == 0x7ff00000)
  40     retval = lx != 0 ? FP_NAN : FP_INFINITE;
  41
  42   return retval;
  43 }