math/w_log.c

   1 /* @(#)w_log.c 5.1 93/09/24 */
   2 /*
   3  * ====================================================
   4  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
   5  *
   6  * Developed at SunPro, a Sun Microsystems, Inc. business.
   7  * Permission to use, copy, modify, and distribute this
   8  * software is freely granted, provided that this notice
   9  * is preserved.
  10  * ====================================================
  11  */
  12
  13 #if defined(LIBM_SCCS) && !defined(lint)
  14 static char rcsid[] = "$NetBSD: w_log.c,v 1.6 1995/05/10 20:49:33 jtc Exp $";
  15 #endif
  16
  17 /*
  18  * wrapper log(x)
  19  */
  20
  21 #include <math.h>
  22 #include "math_private.h"
  23
  24
  25 #ifdef __STDC__
  26         double __log(double x)          /* wrapper log */
  27 #else
  28         double __log(x)                 /* wrapper log */
  29         double x;
  30 #endif
  31 {
  32 #ifdef _IEEE_LIBM
  33         return __ieee754_log(x);
  34 #else
  35         double z;
  36         z = __ieee754_log(x);
  37         if(_LIB_VERSION == _IEEE_ || __isnan(x) || x > 0.0) return z;
  38         if(x==0.0)
  39             return __kernel_standard(x,x,16); /* log(0) */
  40         else
  41             return __kernel_standard(x,x,17); /* log(x<0) */
  42 #endif
  43 }
  44 weak_alias (__log, log)
  45 #ifdef NO_LONG_DOUBLE
  46 strong_alias (__log, __logl)
  47 weak_alias (__log, logl)
  48 #endif