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/* s_ilogbl.c -- long double version of s_ilogb.c.

 * Conversion to IEEE quad long double by Jakub Jelinek, jj@ultra.linux.cz.

 */

/*

 * ====================================================

 * 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.

 * ====================================================

 */

#if defined(LIBM_SCCS) && !defined(lint)

static char rcsid[] = "$NetBSD: $";

#endif

/* ilogbl(long double x)

 * return the binary exponent of non-zero x

 * ilogbl(0) = FP_ILOGB0

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

 * ilogbl(+-Inf) = INT_MAX (no signal is raised)

 */

#include <limits.h>

#include <math.h>

#include "quadmath-imp.h"

#ifndef FP_ILOGB0

# define FP_ILOGB0 INT_MIN

#endif

#ifndef FP_ILOGBNAN

# define FP_ILOGBNAN INT_MAX

#endif

int

ilogbq (__float128 x)

{

        int64_t hx,lx;

        int ix;

        GET_FLT128_WORDS64(hx,lx,x);

        hx &= 0x7fffffffffffffffLL;

        if(hx <= 0x0001000000000000LL) {

            if((hx|lx)==0)

                return FP_ILOGB0;       /* ilogbl(0) = FP_ILOGB0 */

            else                        /* subnormal x */

                if(hx==0) {

                    for (ix = -16431; lx>0; lx<<=1) ix -=1;

                } else {

                    for (ix = -16382, hx<<=15; hx>0; hx<<=1) ix -=1;

                }

            return ix;

        }

        else if (hx<0x7fff000000000000LL) return (hx>>48)-0x3fff;

        else if (FP_ILOGBNAN != INT_MAX) {

            /* ISO C99 requires ilogbl(+-Inf) == INT_MAX.  */

            if (((hx^0x7fff000000000000LL)|lx) == 0)

                return INT_MAX;

        }

        return FP_ILOGBNAN;

}