1  /* Return classification value corresponding to argument.
       2     Copyright (C) 1997-2023 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     <https://www.gnu.org/licenses/>.  */
      18  
      19  #include <math.h>
      20  
      21  #include <math_private.h>
      22  
      23  
      24  int
      25  __fpclassify (double x)
      26  {
      27    uint32_t hx, lx;
      28    int retval = FP_NORMAL;
      29  
      30    EXTRACT_WORDS (hx, lx, x);
      31    lx |= hx & 0xfffff;
      32    hx &= 0x7ff00000;
      33    if ((hx | lx) == 0)
      34      retval = FP_ZERO;
      35    else if (hx == 0)
      36      retval = FP_SUBNORMAL;
      37    else if (hx == 0x7ff00000)
      38      retval = lx != 0 ? FP_NAN : FP_INFINITE;
      39  
      40    return retval;
      41  }
      42  libm_hidden_def (__fpclassify)