Subversion Repositories openrisc_2011-10-31

/* @(#)w_exp2.c 5.1 93/09/24 */

/*

 * ====================================================

 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.

 *

 * Developed at SunPro, a Sun Microsystems, Inc. business.

 * Permission to use, copy, modify, and distribute this

 * software is freely granted, provided that this notice

 * is preserved.

 * ====================================================

 */

/*

FUNCTION

        <<exp2>>, <<exp2f>>--exponential, base 2

INDEX

        exp2

INDEX

        exp2f

ANSI_SYNOPSIS

        #include <math.h>

        double exp2(double <[x]>);

        float exp2f(float <[x]>);

DESCRIPTION

        <<exp2>> and <<exp2f>> calculate 2 ^ <[x]>, that is,

        @ifnottex

        2 raised to the power <[x]>.

        @end ifnottex

        @tex

        $2^x$

        @end tex

        You can use the (non-ANSI) function <<matherr>> to specify

        error handling for these functions.

RETURNS

        On success, <<exp2>> and <<exp2f>> return the calculated value.

        If the result underflows, the returned value is <<0>>.  If the

        result overflows, the returned value is <<HUGE_VAL>>.  In

        either case, <<errno>> is set to <<ERANGE>>.

PORTABILITY

        ANSI C, POSIX.

*/

/*

 * wrapper exp2(x)

 */

#include "fdlibm.h"

#include <errno.h>

#include <math.h>

#ifndef _DOUBLE_IS_32BITS

#ifdef __STDC__

        double exp2(double x)           /* wrapper exp2 */

#else

        double exp2(x)                  /* wrapper exp2 */

        double x;

#endif

{

  return pow(2.0, x);

}

#endif /* defined(_DOUBLE_IS_32BITS) */