xref: /minix3/lib/libm/src/w_log.c (revision 2fe8fb192fe7e8720e3e7a77f928da545e872a6a)
1*2fe8fb19SBen Gras /* @(#)w_log.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_log.c,v 1.10 2007/08/20 16:01:40 drochner Exp $");
16*2fe8fb19SBen Gras #endif
17*2fe8fb19SBen Gras 
18*2fe8fb19SBen Gras /*
19*2fe8fb19SBen Gras  * wrapper log(x)
20*2fe8fb19SBen Gras  */
21*2fe8fb19SBen Gras 
22*2fe8fb19SBen Gras #include "namespace.h"
23*2fe8fb19SBen Gras #include "math.h"
24*2fe8fb19SBen Gras #include "math_private.h"
25*2fe8fb19SBen Gras 
26*2fe8fb19SBen Gras #ifdef __weak_alias
__weak_alias(log,_log)27*2fe8fb19SBen Gras __weak_alias(log, _log)
28*2fe8fb19SBen Gras #endif
29*2fe8fb19SBen Gras 
30*2fe8fb19SBen Gras double
31*2fe8fb19SBen Gras log(double x)		/* wrapper log */
32*2fe8fb19SBen Gras {
33*2fe8fb19SBen Gras #ifdef _IEEE_LIBM
34*2fe8fb19SBen Gras 	return __ieee754_log(x);
35*2fe8fb19SBen Gras #else
36*2fe8fb19SBen Gras 	double z;
37*2fe8fb19SBen Gras 	z = __ieee754_log(x);
38*2fe8fb19SBen Gras 	if(_LIB_VERSION == _IEEE_ || isnan(x) || x > 0.0) return z;
39*2fe8fb19SBen Gras 	if(x==0.0)
40*2fe8fb19SBen Gras 	    return __kernel_standard(x,x,16); /* log(0) */
41*2fe8fb19SBen Gras 	else
42*2fe8fb19SBen Gras 	    return __kernel_standard(x,x,17); /* log(x<0) */
43*2fe8fb19SBen Gras #endif
44*2fe8fb19SBen Gras }
45