math/w_exp2f.c

   1 /*
   2  * wrapper exp2f(x)
   3  */
   4
   5 #include <float.h>
   6 #include <math.h>
   7 #include "math_private.h"
   8
   9 static const float o_threshold= (float) FLT_MAX_EXP;
  10 static const float u_threshold= (float) (FLT_MIN_EXP - FLT_MANT_DIG - 1);
  11
  12 float
  13 __exp2f (float x)               /* wrapper exp2f */
  14 {
  15 #ifdef _IEEE_LIBM
  16   return __ieee754_exp2f (x);
  17 #else
  18   float z;
  19   z = __ieee754_exp2f (x);
  20   if (_LIB_VERSION != _IEEE_ && __finitef (x))
  21     {
  22       if (x > o_threshold)
  23         /* exp2 overflow */
  24         return (float) __kernel_standard ((double) x, (double) x, 144);
  25       else if (x <= u_threshold)
  26         /* exp2 underflow */
  27         return (float) __kernel_standard ((double) x, (double) x, 145);
  28     }
  29   return z;
  30 #endif
  31 }
  32 weak_alias (__exp2f, exp2f)