2017-04-11 21:13:36 +00:00
|
|
|
|
|
|
|
|
/* @(#)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
|
2017-10-07 00:16:47 +00:00
|
|
|
<<exp2>>, <<exp2f>>---exponential, base 2
|
2017-04-11 21:13:36 +00:00
|
|
|
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) */
|
