glibc/math/w_exp2.c
2005-12-14 15:06:39 +00:00

37 lines
732 B
C

/*
* wrapper exp2(x)
*/
#include <float.h>
#include <math.h>
#include "math_private.h"
static const double o_threshold= (double) DBL_MAX_EXP;
static const double u_threshold= (double) (DBL_MIN_EXP - DBL_MANT_DIG - 1);
double
__exp2 (double x) /* wrapper exp2 */
{
#ifdef _IEEE_LIBM
return __ieee754_exp2 (x);
#else
double z;
z = __ieee754_exp2 (x);
if (_LIB_VERSION != _IEEE_ && __finite (x))
{
if (x > o_threshold)
/* exp2 overflow */
return __kernel_standard (x, x, 44);
else if (x <= u_threshold)
/* exp2 underflow */
return __kernel_standard (x, x, 45);
}
return z;
#endif
}
weak_alias (__exp2, exp2)
#ifdef NO_LONG_DOUBLE
strong_alias (__exp2, __exp2l)
weak_alias (__exp2, exp2l)
#endif