lib/signed-nan.h

   1 /* Macros for quiet not-a-number.
   2    Copyright (C) 2023-2024 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 */