RTAI API: base/math/w_log.c Source File

00001 /* @(#)w_log.c 5.1 93/09/24 */
00002 /*
00003  * ====================================================
00004  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
00005  *
00006  * Developed at SunPro, a Sun Microsystems, Inc. business.
00007  * Permission to use, copy, modify, and distribute this
00008  * software is freely granted, provided that this notice 
00009  * is preserved.
00010  * ====================================================
00011  */
00012 
00013 #if defined(LIBM_SCCS) && !defined(lint)
00014 static char rcsid[] = "$NetBSD: w_log.c,v 1.6 1995/05/10 20:49:33 jtc Exp $";
00015 #endif
00016 
00017 /*
00018  * wrapper log(x)
00019  */
00020 
00021 #include "math.h"
00022 #include "mathP.h"
00023 
00024 
00025 #ifdef __STDC__
00026     double log(double x)        /* wrapper log */
00027 #else
00028     double log(x)           /* wrapper log */
00029     double x;
00030 #endif
00031 {
00032 #ifdef _IEEE_LIBM
00033     return __ieee754_log(x);
00034 #else
00035     double z;
00036     z = __ieee754_log(x);
00037     if(_LIB_VERSION == _IEEE_ || isnan(x) || x > 0.0) return z;
00038     if(x==0.0)
00039         return __kernel_standard(x,x,16); /* log(0) */
00040     else 
00041         return __kernel_standard(x,x,17); /* log(x<0) */
00042 #endif
00043 }