/* 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 <math_private.h>

int __ieee754_ilogbl (_Float128 x)

{

	int64_t hx,lx;

	int ix;

	GET_LDOUBLE_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;

}