1/* s_ilogbf.c -- float version of s_ilogb.c.
2 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
3 */
4
5/*
6 * ====================================================
7 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
8 *
9 * Developed at SunPro, a Sun Microsystems, Inc. business.
10 * Permission to use, copy, modify, and distribute this
11 * software is freely granted, provided that this notice
12 * is preserved.
13 * ====================================================
14 */
15
16#ifndef lint
17static char rcsid[] = "$FreeBSD: src/lib/msun/src/s_ilogbf.c,v 1.7 2004/10/09 17:14:28 stefanf Exp $";
18#endif
19
20#include <limits.h>
21
22#include "math.h"
23#include "math_private.h"
24
25	int ilogbf(float x)
26{
27	int32_t hx,ix;
28
29	GET_FLOAT_WORD(hx,x);
30	hx &= 0x7fffffff;
31	if(hx<0x00800000) {
32	    if(hx==0)
33		return FP_ILOGB0;
34	    else			/* subnormal x */
35	        for (ix = -126,hx<<=8; hx>0; hx<<=1) ix -=1;
36	    return ix;
37	}
38	else if (hx<0x7f800000) return (hx>>23)-127;
39	else if (hx>0x7f800000) return FP_ILOGBNAN;
40	else return INT_MAX;
41}
42