lib/libm/src/s_ilogbf.c
/* 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.
 * ====================================================
 */

#include <sys/cdefs.h>
#if defined(LIBM_SCCS) && !defined(lint)
__RCSID("$NetBSD: s_ilogbf.c,v 1.7 2002/05/26 22:01:56 wiz Exp $");
#endif

#include "math.h"
#include "math_private.h"

int
ilogbf(float x)
{
	int32_t hx,ix;

	GET_FLOAT_WORD(hx,x);
	hx &= 0x7fffffff;
	if(hx<0x00800000) {
	    if(hx==0)
		return 0x80000001;	/* ilogb(0) = 0x80000001 */
	    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 return 0x7fffffff;
}
