1*2fe8fb19SBen Gras /* @(#)w_log10.c 5.1 93/09/24 */
2*2fe8fb19SBen Gras /*
3*2fe8fb19SBen Gras * ====================================================
4*2fe8fb19SBen Gras * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
5*2fe8fb19SBen Gras *
6*2fe8fb19SBen Gras * Developed at SunPro, a Sun Microsystems, Inc. business.
7*2fe8fb19SBen Gras * Permission to use, copy, modify, and distribute this
8*2fe8fb19SBen Gras * software is freely granted, provided that this notice
9*2fe8fb19SBen Gras * is preserved.
10*2fe8fb19SBen Gras * ====================================================
11*2fe8fb19SBen Gras */
12*2fe8fb19SBen Gras
13*2fe8fb19SBen Gras #include <sys/cdefs.h>
14*2fe8fb19SBen Gras #if defined(LIBM_SCCS) && !defined(lint)
15*2fe8fb19SBen Gras __RCSID("$NetBSD: w_log2.c,v 1.1 2005/07/21 16:58:39 christos Exp $");
16*2fe8fb19SBen Gras #endif
17*2fe8fb19SBen Gras
18*2fe8fb19SBen Gras /*
19*2fe8fb19SBen Gras * wrapper log2(X)
20*2fe8fb19SBen Gras */
21*2fe8fb19SBen Gras
22*2fe8fb19SBen Gras #include "math.h"
23*2fe8fb19SBen Gras #include "math_private.h"
24*2fe8fb19SBen Gras
25*2fe8fb19SBen Gras
26*2fe8fb19SBen Gras double
log2(double x)27*2fe8fb19SBen Gras log2(double x) /* wrapper log10 */
28*2fe8fb19SBen Gras {
29*2fe8fb19SBen Gras #ifdef _IEEE_LIBM
30*2fe8fb19SBen Gras return __ieee754_log2(x);
31*2fe8fb19SBen Gras #else
32*2fe8fb19SBen Gras double z;
33*2fe8fb19SBen Gras z = __ieee754_log2(x);
34*2fe8fb19SBen Gras if(_LIB_VERSION == _IEEE_ || isnan(x)) return z;
35*2fe8fb19SBen Gras if(x<=0.0) {
36*2fe8fb19SBen Gras if(x==0.0)
37*2fe8fb19SBen Gras return __kernel_standard(x,x,48); /* log2(0) */
38*2fe8fb19SBen Gras else
39*2fe8fb19SBen Gras return __kernel_standard(x,x,49); /* log2(x<0) */
40*2fe8fb19SBen Gras } else
41*2fe8fb19SBen Gras return z;
42*2fe8fb19SBen Gras #endif
43*2fe8fb19SBen Gras }
44