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 (x <= u_threshold || x > o_threshold, 0)
  16       && _LIB_VERSION != _IEEE_ && __finite (x))
  17     /* exp2 overflow: 44, exp2 underflow: 45 */
  18     return __kernel_standard (x, x, 44 + (x <= o_threshold));
  19
  20   return __ieee754_exp2 (x);
  21 }
  22 weak_alias (__exp2, exp2)
  23 #ifdef NO_LONG_DOUBLE
  24 strong_alias (__exp2, __exp2l)
  25 weak_alias (__exp2, exp2l)
  26 #endif