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 #include <sys/cdefs.h>
17 __FBSDID("$FreeBSD$");
18 
19 #include <limits.h>
20 
21 #include "math.h"
22 #include "math_private.h"
23 
ilogbf(float x)24 	int ilogbf(float x)
25 {
26 	int32_t hx,ix;
27 
28 	GET_FLOAT_WORD(hx,x);
29 	hx &= 0x7fffffff;
30 	if(hx<0x00800000) {
31 	    if(hx==0)
32 		return FP_ILOGB0;
33 	    else			/* subnormal x */
34 	        for (ix = -126,hx<<=8; hx>0; hx<<=1) ix -=1;
35 	    return ix;
36 	}
37 	else if (hx<0x7f800000) return (hx>>23)-127;
38 	else if (hx>0x7f800000) return FP_ILOGBNAN;
39 	else return INT_MAX;
40 }
41