/* s_scalblnl.c -- long double version of s_scalbn.c.

 * Conversion to IEEE quad long double by Jakub Jelinek, jj@ultra.linux.cz.

 */

/* @(#)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.

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

 */

#if defined(LIBM_SCCS) && !defined(lint)

static char rcsid[] = "$NetBSD: $";

#endif

/*

 * scalblnl (long double x, long int n)

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

 * manipulation rather than by actually performing an

 * exponentiation or a multiplication.

 */

#include <math.h>

#include <math_private.h>

static const _Float128

two114 = L(2.0769187434139310514121985316880384E+34), /* 0x4071000000000000, 0 */

twom114 = L(4.8148248609680896326399448564623183E-35), /* 0x3F8D000000000000, 0 */

huge   = L(1.0E+4900),

tiny   = L(1.0E-4900);

_Float128 __scalblnl (_Float128 x, long int n)

{

	int64_t k,hx,lx;

	GET_LDOUBLE_WORDS64(hx,lx,x);

        k = (hx>>48)&0x7fff;		/* extract exponent */

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

            if ((lx|(hx&0x7fffffffffffffffULL))==0) return x; /* +-0 */

	    x *= two114;

	    GET_LDOUBLE_MSW64(hx,x);

	    k = ((hx>>48)&0x7fff) - 114;

	}

        if (k==0x7fff) return x+x;		/* NaN or Inf */

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

        if (n> 50000 || k+n > 0x7ffe)

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

	/* Now k and n are bounded we know that k = k+n does not

	   overflow.  */

        k = k+n;

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

	    {SET_LDOUBLE_MSW64(x,(hx&0x8000ffffffffffffULL)|(k<<48)); return x;}

        if (k <= -114)

	  return tiny*__copysignl(tiny,x); 	/*underflow*/

        k += 114;				/* subnormal result */

	SET_LDOUBLE_MSW64(x,(hx&0x8000ffffffffffffULL)|(k<<48));

        return x*twom114;

}