/* s_ilogbl.c -- long double version of s_ilogb.c.
 * Conversion to 80-bit long double by Mark Kettenis, kettenis@openbsd.org.
 */

/*
 * ====================================================
 * 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.
 * ====================================================
 */

/* ilogbl(long 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 <float.h>
#include <math.h>

#include "math_private.h"

int
ilogbl(long double x)
{
        int32_t esx,hx,lx,ix;

        GET_LDOUBLE_WORDS(esx,hx,lx,x);
        esx &= 0x7fff;
        if(esx==0) {
            if((hx|lx)==0) 
                return FP_ILOGB0;       /* ilogb(0) = FP_ILOGB0 */
            else                        /* subnormal x */
                if(hx==0) {
                    for (ix = -16414; lx>0; lx<<=1) ix -=1;
                } else {
                    for (ix = -16382; hx>0; hx<<=1) ix -=1;
                }
            return ix;
        }
        else if (esx<0x7fff) return (esx)-16383;
        else if ((hx&0x7fffffff|lx)!=0) return FP_ILOGBNAN;
        else return INT_MAX;
}
DEF_STD(ilogbl);