source: trunk/libs/newlib/src/newlib/libm/math/w_atanh.c @ 543

Last change on this file since 543 was 444, checked in by satin@…, 6 years ago

add newlib,libalmos-mkh, restructure shared_syscalls.h and mini-libc
File size: 2.6 KB
Line 
1
2/* @(#)w_atanh.c 5.1 93/09/24 */
3/*
4 * ====================================================
5 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
6 *
7 * Developed at SunPro, 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/*
15FUNCTION
16        <<atanh>>, <<atanhf>>---inverse hyperbolic tangent
17
18INDEX
19        atanh
20INDEX
21        atanhf
22
23SYNOPSIS
24        #include <math.h>
25        double atanh(double <[x]>);
26        float atanhf(float <[x]>);
27
28DESCRIPTION
29        <<atanh>> calculates the inverse hyperbolic tangent of <[x]>.
30
31        <<atanhf>> is identical, other than taking and returning
32        <<float>> values.
33
34RETURNS
35        <<atanh>> and <<atanhf>> return the calculated value.
36
37        If
38        @ifnottex
39        |<[x]>|
40        @end ifnottex
41        @tex
42        $|x|$
43        @end tex
44        is greater than 1, the global <<errno>> is set to <<EDOM>> and
45        the result is a NaN.  A <<DOMAIN error>> is reported.
46
47        If
48        @ifnottex
49        |<[x]>|
50        @end ifnottex
51        @tex
52        $|x|$
53        @end tex
54        is 1, the global <<errno>> is set to <<EDOM>>; and the result is
55        infinity with the same sign as <<x>>.  A <<SING error>> is reported.
56
57        You can modify the error handling for these routines using
58        <<matherr>>.
59
60PORTABILITY
61        Neither <<atanh>> nor <<atanhf>> are ANSI C.
62
63QUICKREF
64        atanh - pure
65        atanhf - pure
66
67
68*/
69
70/*
71 * wrapper atanh(x)
72 */
73
74#include "fdlibm.h"
75#include <errno.h>
76
77#ifndef _DOUBLE_IS_32BITS
78
79#ifdef __STDC__
80        double atanh(double x)          /* wrapper atanh */
81#else
82        double atanh(x)                 /* wrapper atanh */
83        double x;
84#endif
85{
86#ifdef _IEEE_LIBM
87        return __ieee754_atanh(x);
88#else
89        double z,y;
90        struct exception exc;
91        z = __ieee754_atanh(x);
92        if(_LIB_VERSION == _IEEE_ || isnan(x)) return z;
93        y = fabs(x);
94        if(y>=1.0) {
95            if(y>1.0) {
96                /* atanh(|x|>1) */
97                exc.type = DOMAIN;
98                exc.name = "atanh";
99                exc.err = 0;
100                exc.arg1 = exc.arg2 = x;
101                exc.retval = 0.0/0.0;
102                if (_LIB_VERSION == _POSIX_)
103                  errno = EDOM;
104                else if (!matherr(&exc)) {
105                  errno = EDOM;
106                }
107            } else { 
108                /* atanh(|x|=1) */
109                exc.type = SING;
110                exc.name = "atanh";
111                exc.err = 0;
112                exc.arg1 = exc.arg2 = x;
113                exc.retval = x/0.0;     /* sign(x)*inf */
114                if (_LIB_VERSION == _POSIX_)
115                  errno = EDOM;
116                else if (!matherr(&exc)) {
117                  errno = EDOM;
118                }
119            }
120            if (exc.err != 0)
121              errno = exc.err;
122            return exc.retval; 
123        } else
124            return z;
125#endif
126}
127
128#endif /* defined(_DOUBLE_IS_32BITS) */
129
130
131
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