Subversion Repositories openrisc

/* @(#)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

@ifnottex

<[val]> times 2 to the power <[exp]>.

@end ifnottex

@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 */