winsup/cygwin/math/coshl.c

   1 /**
   2  * This file has no copyright assigned and is placed in the Public Domain.
   3  * This file is part of the mingw-w64 runtime package.
   4  * No warranty is given; refer to the file DISCLAIMER.PD within this package.
   5  */
   6 #include "cephes_mconf.h"
   7
   8 #ifndef _SET_ERRNO
   9 #define _SET_ERRNO(x)
  10 #endif
  11
  12 long double coshl(long double x)
  13 {
  14   long double y;
  15   int x_class = fpclassify (x);
  16   if (x_class == FP_NAN)
  17     {
  18       errno = EDOM;
  19       return x;
  20     }
  21   else if (x_class == FP_INFINITE)
  22     {
  23        errno = ERANGE;
  24        return INFINITY;
  25     }
  26   x = fabsl (x);
  27   if (x > (MAXLOGL + LOGE2L))
  28     {
  29       errno = ERANGE;
  30 #ifdef INFINITIES
  31       return (INFINITYL);
  32 #else
  33       return (MAXNUML);
  34 #endif
  35     }
  36   if (x >= (MAXLOGL - LOGE2L))
  37     {
  38       y = expl(0.5L * x);
  39       y = (0.5L * y) * y;
  40       return y;
  41     }
  42   y = expl(x);
  43   y = 0.5L * (y + 1.0L / y);
  44   return y;
  45 }