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

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

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

*/

/* @(#)s_ilogb.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_ilogb.c,v 1.9 2004/10/09 17:14:28 stefanf Exp $";

#endif

#endif //__SYMBIAN32__

/* ilogb(double x)

 * return the binary exponent of non-zero x

 * ilogb(0) = FP_ILOGB0

 * ilogb(NaN) = FP_ILOGBNAN (no signal is raised)

 * ilogb(inf) = INT_MAX (no signal is raised)

 */

#include <limits.h>

#include <math.h>

#include "math_private.h"

EXPORT_C int ilogb(double x)

{

	int32_t hx,lx,ix;

	EXTRACT_WORDS(hx,lx,x);

	hx &= 0x7fffffff;

	if(hx<0x00100000) {

	    if((hx|lx)==0)

		return FP_ILOGB0;

	    else			/* subnormal x */

		if(hx==0) {

		    for (ix = -1043; lx>0; lx<<=1) ix -=1;

		} else {

		    for (ix = -1022,hx<<=11; hx>0; hx<<=1) ix -=1;

		}

	    return ix;

	}

	else if (hx<0x7ff00000) return (hx>>20)-1023;

	else if (hx>0x7ff00000 || lx!=0) return FP_ILOGBNAN;

	else return INT_MAX;

}