/* s_ilogbf.c -- float version of s_ilogb.c.

 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.

 */

/*

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

 * 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: s_ilogbf.c,v 1.4 1995/05/10 20:47:31 jtc Exp $";

#endif

#include <limits.h>

#include <math.h>

#include <math_private.h>

int __ieee754_ilogbf(float x)

{

	int32_t hx,ix;

	GET_FLOAT_WORD(hx,x);

	hx &= 0x7fffffff;

	if(hx<0x00800000) {

	    if(hx==0)

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

	    else			/* subnormal x */

	        for (ix = -126,hx<<=8; hx>0; hx<<=1) ix -=1;

	    return ix;

	}

	else if (hx<0x7f800000) return (hx>>23)-127;

	else if (FP_ILOGBNAN != INT_MAX) {

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

	    if (hx==0x7f800000)

		return INT_MAX;

	}

	return FP_ILOGBNAN;

}