POK
/home/jaouen/pok_official/pok/trunk/libpok/libm/log.c
00001 /*
00002  *                               POK header
00003  * 
00004  * The following file is a part of the POK project. Any modification should
00005  * made according to the POK licence. You CANNOT use this file or a part of
00006  * this file is this part of a file for your own project
00007  *
00008  * For more information on the POK licence, please see our LICENCE FILE
00009  *
00010  * Please follow the coding guidelines described in doc/CODING_GUIDELINES
00011  *
00012  *                                      Copyright (c) 2007-2009 POK team 
00013  *
00014  * Created by julien on Fri Jan 30 14:41:34 2009 
00015  */
00016 
00017 /* @(#)w_log.c 5.1 93/09/24 */
00018 /*
00019  * ====================================================
00020  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
00021  *
00022  * Developed at SunPro, a Sun Microsystems, Inc. business.
00023  * Permission to use, copy, modify, and distribute this
00024  * software is freely granted, provided that this notice
00025  * is preserved.
00026  * ====================================================
00027  */
00028 
00029 #ifdef POK_NEEDS_LIBMATH
00030 
00031 /*
00032  * wrapper log(x)
00033  */
00034 
00035 #include <libm.h>
00036 #include "namespace.h"
00037 #include "math_private.h"
00038 
00039 #ifdef __weak_alias
00040 __weak_alias(log, _log)
00041 #endif
00042 
00043 double
00044 log(double x)           /* wrapper log */
00045 {
00046 #ifdef _IEEE_LIBM
00047         return __ieee754_log(x);
00048 #else
00049         double z;
00050         z = __ieee754_log(x);
00051         if(_LIB_VERSION == _IEEE_ || isnan(x) || x > 0.0) return z;
00052         if(x==0.0)
00053             return __kernel_standard(x,x,16); /* log(0) */
00054         else
00055             return __kernel_standard(x,x,17); /* log(x<0) */
00056 #endif
00057 }
00058 
00059 #endif