/*

 * Copyright (c) 1998, 2001, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

/* ilogb(double x)

 * return the binary exponent of non-zero x

 * ilogb(0) = 0x80000001

 * ilogb(inf/NaN) = 0x7fffffff (no signal is raised)

 */

#include "fdlibm.h"

#ifdef __STDC__

        int ilogb(double x)

#else

        int ilogb(x)

        double x;

#endif

{

        int hx,lx,ix;

        hx  = (__HI(x))&0x7fffffff;     /* high word of x */

        if(hx<0x00100000) {

            lx = __LO(x);

            if((hx|lx)==0)

                return 0x80000001;      /* ilogb(0) = 0x80000001 */

            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 return 0x7fffffff;

}