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w_atanh.c
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1 
2 /* @(#)w_atanh.c 1.3 95/01/18 */
3 /*
4  * ====================================================
5  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
6  *
7  * Developed at SunSoft, a Sun Microsystems, Inc. business.
8  * Permission to use, copy, modify, and distribute this
9  * software is freely granted, provided that this notice
10  * is preserved.
11  * ====================================================
12  */
13 /*
14  * wrapper atanh(x)
15  */
16 
17 #include "fdlibm.h"
18 
19 
20 #ifdef __STDC__
21  double atanh(double x) /* wrapper atanh */
22 #else
23  double atanh(x) /* wrapper atanh */
24  double x;
25 #endif
26 {
27 #ifdef _IEEE_LIBM
28  return __ieee754_atanh(x);
29 #else
30  double z,y;
31  z = __ieee754_atanh(x);
32  if(_LIB_VERSION == _IEEE_ || isnan(x)) return z;
33  y = fabs(x);
34  if(y>=1.0) {
35  if(y>1.0)
36  return __kernel_standard(x,x,30); /* atanh(|x|>1) */
37  else
38  return __kernel_standard(x,x,31); /* atanh(|x|==1) */
39  } else
40  return z;
41 #endif
42 }