1 /* @(#)w_log10.c 5.1 93/09/24 */
2 /*
3 * ====================================================
4 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
5 *
6 * Developed at SunPro, a Sun Microsystems, Inc. business.
7 * Permission to use, copy, modify, and distribute this
8 * software is freely granted, provided that this notice
9 * is preserved.
10 * ====================================================
11 */
12
13 #include <sys/cdefs.h>
14 #if defined(LIBM_SCCS) && !defined(lint)
15 __RCSID("$NetBSD: w_log2.c,v 1.2 2024/07/16 14:52:50 riastradh Exp $");
16 #endif
17
18 /*
19 * wrapper log2(X)
20 */
21
22 #include "namespace.h"
23
24 #include "math.h"
25 #include "math_private.h"
26
27 #ifndef __HAVE_LONG_DOUBLE
__weak_alias(log2l,_log2l)28 __weak_alias(log2l, _log2l)
29 __strong_alias(_log2l, _log2)
30 #endif
31
32 __weak_alias(log2, _log2)
33 double
34 log2(double x) /* wrapper log10 */
35 {
36 #ifdef _IEEE_LIBM
37 return __ieee754_log2(x);
38 #else
39 double z;
40 z = __ieee754_log2(x);
41 if(_LIB_VERSION == _IEEE_ || isnan(x)) return z;
42 if(x<=0.0) {
43 if(x==0.0)
44 return __kernel_standard(x,x,48); /* log2(0) */
45 else
46 return __kernel_standard(x,x,49); /* log2(x<0) */
47 } else
48 return z;
49 #endif
50 }
51