82 lines
1.7 KiB
C
82 lines
1.7 KiB
C
|
|
||
|
|
/* @(#)s_ldexp.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
|
||
|
|
<<ldexp>>, <<ldexpf>>---load exponent
|
||
|
|
|
||
|
|
INDEX
|
||
|
|
ldexp
|
||
|
|
INDEX
|
||
|
|
ldexpf
|
||
|
|
|
||
|
|
ANSI_SYNOPSIS
|
||
|
|
#include <math.h>
|
||
|
|
double ldexp(double <[val]>, int <[exp]>);
|
||
|
|
float ldexpf(float <[val]>, int <[exp]>);
|
||
|
|
|
||
|
|
TRAD_SYNOPSIS
|
||
|
|
#include <math.h>
|
||
|
|
|
||
|
|
double ldexp(<[val]>, <[exp]>)
|
||
|
|
double <[val]>;
|
||
|
|
int <[exp]>;
|
||
|
|
|
||
|
|
float ldexpf(<[val]>, <[exp]>)
|
||
|
|
float <[val]>;
|
||
|
|
int <[exp]>;
|
||
|
|
|
||
|
|
|
||
|
|
DESCRIPTION
|
||
|
|
<<ldexp>> calculates the value
|
||
|
|
@ifinfo
|
||
|
|
<[val]> times 2 to the power <[exp]>.
|
||
|
|
@end ifinfo
|
||
|
|
@tex
|
||
|
|
$val\times 2^{exp}$.
|
||
|
|
@end tex
|
||
|
|
<<ldexpf>> is identical, save that it takes and returns <<float>>
|
||
|
|
rather than <<double>> values.
|
||
|
|
|
||
|
|
RETURNS
|
||
|
|
<<ldexp>> returns the calculated value.
|
||
|
|
|
||
|
|
Underflow and overflow both set <<errno>> to <<ERANGE>>.
|
||
|
|
On underflow, <<ldexp>> and <<ldexpf>> return 0.0.
|
||
|
|
On overflow, <<ldexp>> returns plus or minus <<HUGE_VAL>>.
|
||
|
|
|
||
|
|
PORTABILITY
|
||
|
|
<<ldexp>> is ANSI, <<ldexpf>> is an extension.
|
||
|
|
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include "fdlibm.h"
|
||
|
|
#include <errno.h>
|
||
|
|
|
||
|
|
#ifndef _DOUBLE_IS_32BITS
|
||
|
|
|
||
|
|
#ifdef __STDC__
|
||
|
|
double ldexp(double value, int exp)
|
||
|
|
#else
|
||
|
|
double ldexp(value, exp)
|
||
|
|
double value; int exp;
|
||
|
|
#endif
|
||
|
|
{
|
||
|
|
if(!finite(value)||value==0.0) return value;
|
||
|
|
value = scalbn(value,exp);
|
||
|
|
if(!finite(value)||value==0.0) errno = ERANGE;
|
||
|
|
return value;
|
||
|
|
}
|
||
|
|
|
||
|
|
#endif /* _DOUBLE_IS_32BITS */
|