/* origin: FreeBSD /usr/src/lib/msun/src/s_scalbnf.c */
/*
 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
 */
/*
 * ====================================================
 * 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.
 * ====================================================
 */

#include "libm.h"

static const float
two25  = 3.355443200e+07,  /* 0x4c000000 */
twom25 = 2.9802322388e-08, /* 0x33000000 */
huge   = 1.0e+30,
tiny   = 1.0e-30;

float scalbnf(float x, int n)
{
	int32_t k, ix;
	GET_FLOAT_WORD(ix, x);
	k = (ix&0x7f800000)>>23;           /* extract exponent */
	if (k == 0) {                      /* 0 or subnormal x */
		if ((ix&0x7fffffff) == 0)  /* +-0 */
			return x;
		x *= two25;
		GET_FLOAT_WORD(ix, x);
		k = ((ix&0x7f800000)>>23) - 25;
		if (n < -50000)
			return tiny*x;  /*underflow*/
	}
	if (k == 0xff)                     /* NaN or Inf */
		return x + x;
	k = k + n;
	if (k > 0xfe)
		return huge*copysignf(huge, x);  /* overflow  */
	if (k > 0) {                       /* normal result */
		SET_FLOAT_WORD(x, (ix&0x807fffff)|(k<<23));
		return x;
	}
	if (k <= -25)
		if (n > 50000)  /* in case integer overflow in n+k */
			return huge*copysignf(huge,x);  /*overflow*/
		return tiny*copysignf(tiny, x);  /*underflow*/
	k += 25;                           /* subnormal result */
	SET_FLOAT_WORD(x, (ix&0x807fffff)|(k<<23));
	return x*twom25;
}