1 | /* Return arc hyperbole cosine for float value. |
---|
2 | Copyright (C) 1997 Free Software Foundation, Inc. |
---|
3 | This file is part of the GNU C Library. |
---|
4 | Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997. |
---|
5 | |
---|
6 | The GNU C Library is free software; you can redistribute it and/or |
---|
7 | modify it under the terms of the GNU Lesser General Public |
---|
8 | License as published by the Free Software Foundation; either |
---|
9 | version 2.1 of the License, or (at your option) any later version. |
---|
10 | |
---|
11 | The GNU C Library is distributed in the hope that it will be useful, |
---|
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
---|
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
---|
14 | Lesser General Public License for more details. |
---|
15 | |
---|
16 | You should have received a copy of the GNU Lesser General Public |
---|
17 | License along with the GNU C Library; if not, write to the Free |
---|
18 | Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
---|
19 | 02111-1307 USA. */ |
---|
20 | |
---|
21 | #include <complex.h> |
---|
22 | #include <math.h> |
---|
23 | #include "math_private.h" |
---|
24 | |
---|
25 | __complex__ float |
---|
26 | __cacoshf (__complex__ float x) |
---|
27 | { |
---|
28 | __complex__ float res; |
---|
29 | int rcls = fpclassify (__real__ x); |
---|
30 | int icls = fpclassify (__imag__ x); |
---|
31 | |
---|
32 | if (rcls <= FP_INFINITE || icls <= FP_INFINITE) |
---|
33 | { |
---|
34 | if (icls == FP_INFINITE) |
---|
35 | { |
---|
36 | __real__ res = HUGE_VALF; |
---|
37 | |
---|
38 | if (rcls == FP_NAN) |
---|
39 | __imag__ res = __nanf (""); |
---|
40 | else |
---|
41 | __imag__ res = __copysignf ((rcls == FP_INFINITE |
---|
42 | ? (__real__ x < 0.0 |
---|
43 | ? M_PI - M_PI_4 : M_PI_4) |
---|
44 | : M_PI_2), __imag__ x); |
---|
45 | } |
---|
46 | else if (rcls == FP_INFINITE) |
---|
47 | { |
---|
48 | __real__ res = HUGE_VALF; |
---|
49 | |
---|
50 | if (icls >= FP_ZERO) |
---|
51 | __imag__ res = __copysignf (signbit (__real__ x) ? M_PI : 0.0, |
---|
52 | __imag__ x); |
---|
53 | else |
---|
54 | __imag__ res = __nanf (""); |
---|
55 | } |
---|
56 | else |
---|
57 | { |
---|
58 | __real__ res = __nanf (""); |
---|
59 | __imag__ res = __nanf (""); |
---|
60 | } |
---|
61 | } |
---|
62 | else if (rcls == FP_ZERO && icls == FP_ZERO) |
---|
63 | { |
---|
64 | __real__ res = 0.0; |
---|
65 | __imag__ res = __copysignf (M_PI_2, __imag__ x); |
---|
66 | } |
---|
67 | else |
---|
68 | { |
---|
69 | #if 1 |
---|
70 | __complex__ float y; |
---|
71 | |
---|
72 | __real__ y = (__real__ x - __imag__ x) * (__real__ x + __imag__ x) - 1.0; |
---|
73 | __imag__ y = 2.0 * __real__ x * __imag__ x; |
---|
74 | |
---|
75 | y = __csqrtf (y); |
---|
76 | |
---|
77 | __real__ y += __real__ x; |
---|
78 | __imag__ y += __imag__ x; |
---|
79 | |
---|
80 | res = __clogf (y); |
---|
81 | #else |
---|
82 | float re2 = __real__ x * __real__ x; |
---|
83 | float im2 = __imag__ x * __imag__ x; |
---|
84 | float sq = re2 - im2 - 1.0; |
---|
85 | float ro = __ieee754_sqrtf (sq * sq + 4 * re2 * im2); |
---|
86 | float a = __ieee754_sqrtf ((sq + ro) / 2.0); |
---|
87 | float b = __ieee754_sqrtf ((-sq + ro) / 2.0); |
---|
88 | |
---|
89 | __real__ res = 0.5 * __ieee754_logf (re2 + __real__ x * 2 * a |
---|
90 | + im2 + __imag__ x * 2 * b |
---|
91 | + ro); |
---|
92 | __imag__ res = __ieee754_atan2f (__imag__ x + b, __real__ x + a); |
---|
93 | #endif |
---|
94 | } |
---|
95 | |
---|
96 | return res; |
---|
97 | } |
---|
98 | weak_alias (__cacoshf, cacoshf) |
---|