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 "math.h"
17 #include "math_private.h"
18
19 int
ilogbf(float x)20 ilogbf(float x)
21 {
22 int32_t hx,ix;
23
24 GET_FLOAT_WORD(hx,x);
25 hx &= 0x7fffffff;
26 if(hx<0x00800000) {
27 if(hx==0)
28 return 0x80000001; /* ilogb(0) = 0x80000001 */
29 else /* subnormal x */
30 for (ix = -126,hx<<=8; hx>0; hx<<=1) ix -=1;
31 return ix;
32 }
33 else if (hx<0x7f800000) return (hx>>23)-127;
34 else return 0x7fffffff;
35 }
36