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

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

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

*/

/* @(#)s_logb.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_logb.c,v 1.9 2003/07/23 04:53:46 peter Exp $";

#endif

#endif //__SYMBIAN32__

/*

 * double logb(x)

 * IEEE 754 logb. Included to pass IEEE test suite. Not recommend.

 * Use ilogb instead.

 */

#include <math.h>

#include "math_private.h"

EXPORT_C double

logb(double x)

{

	int32_t lx,ix;

	EXTRACT_WORDS(ix,lx,x);

	ix &= 0x7fffffff;			/* high |x| */

	if((ix|lx)==0) return -1.0/fabs(x);

	if(ix>=0x7ff00000) return x*x;

	if((ix>>=20)==0) 			/* IEEE 754 logb */

		return -1022.0;

	else

		return (double) (ix-1023);

}