math/w_exp2.c

   1 /*
   2  * wrapper exp2(x)
   3  */
   4
   5 #include <float.h>
   6 #include <math.h>
   7 #include <math_private.h>
   8
   9 static const double o_threshold = (double) DBL_MAX_EXP;
  10 static const double u_threshold = (double) (DBL_MIN_EXP - DBL_MANT_DIG - 1);
  11
  12 double
  13 __exp2 (double x)
  14 {
  15   if (__builtin_expect (islessequal (x, u_threshold)
  16                         || isgreater (x, o_threshold), 0)
  17       && _LIB_VERSION != _IEEE_ && __finite (x))
  18     /* exp2 overflow: 44, exp2 underflow: 45 */
  19     return __kernel_standard (x, x, 44 + (x <= o_threshold));
  20
  21   return __ieee754_exp2 (x);
  22 }
  23 weak_alias (__exp2, exp2)
  24 #ifdef NO_LONG_DOUBLE
  25 strong_alias (__exp2, __exp2l)
  26 weak_alias (__exp2, exp2l)
  27 #endif