/*--------------------------------------------------------------------

 *© Portions copyright (c) 2006 Nokia Corporation.  All rights reserved.

 *--------------------------------------------------------------------

*/

/* @(#)s_scalbn.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.

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

 */

#ifndef __SYMBIAN32__

#ifndef lint

static char rcsid[] = "$FreeBSD: src/lib/msun/src/s_scalbn.c,v 1.11 2005/03/07 21:27:37 das Exp $";

#endif

#endif //__SYMBIAN32__

/*

 * scalbn (double x, int n)

 * scalbn(x,n) returns x* 2**n  computed by  exponent

 * manipulation rather than by actually performing an

 * exponentiation or a multiplication.

 */

#include <sys/cdefs.h>

#include <float.h>

#include <math.h>

#include "math_private.h"

static const double

two54   =  1.80143985094819840000e+16, /* 0x43500000, 0x00000000 */

twom54  =  5.55111512312578270212e-17, /* 0x3C900000, 0x00000000 */

huge   = 1.0e+300,

tiny   = 1.0e-300;

EXPORT_C double scalbn (double x, int n)

{

	int32_t k,hx,lx;

	EXTRACT_WORDS(hx,lx,x);

        k = (hx&0x7ff00000)>>20;		/* extract exponent */

        if (k==0) {				/* 0 or subnormal x */

            if ((lx|(hx&0x7fffffff))==0) return x; /* +-0 */

	    x *= two54;

	    GET_HIGH_WORD(hx,x);

	    k = ((hx&0x7ff00000)>>20) - 54;

            if (n< -50000) return tiny*x; 	/*underflow*/

	    }

        if (k==0x7ff) return x+x;		/* NaN or Inf */

        k = k+n;

        if (k >  0x7fe) return huge*copysign(huge,x); /* overflow  */

        if (k > 0) 				/* normal result */

	    {SET_HIGH_WORD(x,(hx&0x800fffff)|(k<<20)); return x;}

        if (k <= -54)

            if (n > 50000) 	/* in case integer overflow in n+k */

		return huge*copysign(huge,x);	/*overflow*/

	    else return tiny*copysign(tiny,x); 	/*underflow*/

        k += 54;				/* subnormal result */

	SET_HIGH_WORD(x,(hx&0x800fffff)|(k<<20));

        return x*twom54;

}

#ifndef __SYMBIAN32__

#if (LDBL_MANT_DIG == 53)

__weak_reference(scalbn, ldexpl);

__weak_reference(scalbn, scalbnl);

#endif

#endif //__SYMBIAN32__