1  /* Macros for quiet not-a-number.
       2     Copyright (C) 2023 Free Software Foundation, Inc.
       3  
       4     This program is free software: you can redistribute it and/or modify
       5     it under the terms of the GNU General Public License as published by
       6     the Free Software Foundation, either version 3 of the License, or
       7     (at your option) any later version.
       8  
       9     This program is distributed in the hope that it will be useful,
      10     but WITHOUT ANY WARRANTY; without even the implied warranty of
      11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      12     GNU General Public License for more details.
      13  
      14     You should have received a copy of the GNU General Public License
      15     along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
      16  
      17  #ifndef _SIGNED_NAN_H
      18  #define _SIGNED_NAN_H
      19  
      20  #include <math.h>
      21  
      22  #include "nan.h"
      23  
      24  
      25  /* Returns a quiet 'float' NaN with sign bit == 0.  */
      26  _GL_UNUSED static float
      27  positive_NaNf ()
      28  {
      29    /* 'volatile' works around a GCC bug:
      30       <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111655>  */
      31    float volatile nan = NaNf ();
      32    return (signbit (nan) ? - nan : nan);
      33  }
      34  
      35  /* Returns a quiet 'float' NaN with sign bit == 1.  */
      36  _GL_UNUSED static float
      37  negative_NaNf ()
      38  {
      39    /* 'volatile' works around a GCC bug:
      40       <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111655>  */
      41    float volatile nan = NaNf ();
      42    return (signbit (nan) ? nan : - nan);
      43  }
      44  
      45  
      46  /* Returns a quiet 'double' NaN with sign bit == 0.  */
      47  _GL_UNUSED static double
      48  positive_NaNd ()
      49  {
      50    /* 'volatile' works around a GCC bug:
      51       <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111655>  */
      52    double volatile nan = NaNd ();
      53    return (signbit (nan) ? - nan : nan);
      54  }
      55  
      56  /* Returns a quiet 'double' NaN with sign bit == 1.  */
      57  _GL_UNUSED static double
      58  negative_NaNd ()
      59  {
      60    /* 'volatile' works around a GCC bug:
      61       <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111655>  */
      62    double volatile nan = NaNd ();
      63    return (signbit (nan) ? nan : - nan);
      64  }
      65  
      66  
      67  /* Returns a quiet 'long double' NaN with sign bit == 0.  */
      68  _GL_UNUSED static long double
      69  positive_NaNl ()
      70  {
      71    /* 'volatile' works around a GCC bug:
      72       <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111655>  */
      73    long double volatile nan = NaNl ();
      74    return (signbit (nan) ? - nan : nan);
      75  }
      76  
      77  /* Returns a quiet 'long double' NaN with sign bit == 1.  */
      78  _GL_UNUSED static long double
      79  negative_NaNl ()
      80  {
      81    /* 'volatile' works around a GCC bug:
      82       <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111655>  */
      83    long double volatile nan = NaNl ();
      84    return (signbit (nan) ? nan : - nan);
      85  }
      86  
      87  
      88  #endif /* _SIGNED_NAN_H */