newlib/libm/common/s_nan.c

   1 /*
   2  * nan () returns a nan.
   3  * Added by Cygnus Support.
   4  */
   5
   6 /*
   7 FUNCTION
   8         <<nan>>, <<nanf>>---representation of ``Not a Number''
   9
  10 INDEX
  11         nan
  12 INDEX
  13         nanf
  14
  15 SYNOPSIS
  16         #include <math.h>
  17         double nan(const char *<[unused]>);
  18         float nanf(const char *<[unused]>);
  19
  20
  21 DESCRIPTION
  22         <<nan>> and <<nanf>> return an IEEE NaN (Not a Number) in
  23         double- and single-precision arithmetic respectively.  The
  24         argument is currently disregarded.
  25
  26 QUICKREF
  27         nan - pure
  28
  29 */
  30
  31 #include "fdlibm.h"
  32
  33 #ifndef _DOUBLE_IS_32BITS
  34
  35         double nan(const char *unused)
  36 {
  37         double x;
  38
  39 #if __GNUC_PREREQ (3, 3)
  40         x = __builtin_nan("");
  41 #else
  42         INSERT_WORDS(x,0x7ff80000,0);
  43 #endif
  44         return x;
  45 }
  46
  47 #endif /* _DOUBLE_IS_32BITS */