lib/libm/src/w_atanh.c

   1 /* @(#)w_atanh.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 #include <sys/cdefs.h>
  14 #if defined(LIBM_SCCS) && !defined(lint)
  15 __RCSID("$NetBSD: w_atanh.c,v 1.9 2002/05/26 22:02:00 wiz Exp $");
  16 #endif
  17
  18 /*
  19  * wrapper atanh(x)
  20  */
  21
  22 #include "math.h"
  23 #include "math_private.h"
  24
  25
  26 double
  27 atanh(double x)         /* wrapper atanh */
  28 {
  29 #ifdef _IEEE_LIBM
  30         return __ieee754_atanh(x);
  31 #else
  32         double z,y;
  33         z = __ieee754_atanh(x);
  34         if(_LIB_VERSION == _IEEE_ || isnan(x)) return z;
  35         y = fabs(x);
  36         if(y>=1.0) {
  37             if(y>1.0)
  38                 return __kernel_standard(x,x,30); /* atanh(|x|>1) */
  39             else
  40                 return __kernel_standard(x,x,31); /* atanh(|x|==1) */
  41         } else
  42             return z;
  43 #endif
  44 }