1 /* sf_ilogb.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 <limits.h>
17 #include "fdlibm.h"
18
ilogbf(float x)19 int ilogbf(float x)
20 {
21 __int32_t hx,ix;
22
23 GET_FLOAT_WORD(hx,x);
24 hx &= 0x7fffffff;
25 if(FLT_UWORD_IS_ZERO(hx)) {
26 (void) __math_invalidf(0.0);
27 return FP_ILOGB0; /* ilogb(0) = special case error */
28 }
29 if(FLT_UWORD_IS_SUBNORMAL(hx)) {
30 for (ix = -126,hx<<=8; hx>0; hx<<=1) ix -=1;
31 return ix;
32 }
33 #if FP_ILOGBNAN != INT_MAX
34 else if (FLT_UWORD_IS_NAN(hx)) {
35 (void) __math_invalidf(0.0);
36 return FP_ILOGBNAN; /* NAN */
37 }
38 #endif
39 else if (!FLT_UWORD_IS_FINITE(hx)) {
40 (void) __math_invalidf(0.0);
41 return INT_MAX;
42 }
43 else return (hx>>23)-127;
44 }
45
46 _MATH_ALIAS_i_f(ilogb)
47
