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 }