Mercurial > hg > CbC > CbC_gcc
comparison libquadmath/math/ctanq.c @ 111:04ced10e8804
gcc 7
author | kono |
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date | Fri, 27 Oct 2017 22:46:09 +0900 |
parents | |
children | 1830386684a0 |
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68:561a7518be6b | 111:04ced10e8804 |
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1 /* Complex tangent function for complex __float128. | |
2 Copyright (C) 1997-2012 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, see | |
18 <http://www.gnu.org/licenses/>. */ | |
19 | |
20 #include "quadmath-imp.h" | |
21 | |
22 #ifdef HAVE_FENV_H | |
23 # include <fenv.h> | |
24 #endif | |
25 | |
26 | |
27 __complex128 | |
28 ctanq (__complex128 x) | |
29 { | |
30 __complex128 res; | |
31 | |
32 if (__builtin_expect (!finiteq (__real__ x) || !finiteq (__imag__ x), 0)) | |
33 { | |
34 if (__quadmath_isinf_nsq (__imag__ x)) | |
35 { | |
36 __real__ res = copysignq (0.0Q, __real__ x); | |
37 __imag__ res = copysignq (1.0Q, __imag__ x); | |
38 } | |
39 else if (__real__ x == 0.0Q) | |
40 { | |
41 res = x; | |
42 } | |
43 else | |
44 { | |
45 __real__ res = nanq (""); | |
46 __imag__ res = nanq (""); | |
47 | |
48 #ifdef HAVE_FENV_H | |
49 if (__quadmath_isinf_nsq (__real__ x)) | |
50 feraiseexcept (FE_INVALID); | |
51 #endif | |
52 } | |
53 } | |
54 else | |
55 { | |
56 __float128 sinrx, cosrx; | |
57 __float128 den; | |
58 const int t = (int) ((FLT128_MAX_EXP - 1) * M_LN2q / 2.0Q); | |
59 int rcls = fpclassifyq (__real__ x); | |
60 | |
61 /* tan(x+iy) = (sin(2x) + i*sinh(2y))/(cos(2x) + cosh(2y)) | |
62 = (sin(x)*cos(x) + i*sinh(y)*cosh(y)/(cos(x)^2 + sinh(y)^2). */ | |
63 | |
64 if (__builtin_expect (rcls != QUADFP_SUBNORMAL, 1)) | |
65 { | |
66 sincosq (__real__ x, &sinrx, &cosrx); | |
67 } | |
68 else | |
69 { | |
70 sinrx = __real__ x; | |
71 cosrx = 1.0Q; | |
72 } | |
73 | |
74 if (fabsq (__imag__ x) > t) | |
75 { | |
76 /* Avoid intermediate overflow when the real part of the | |
77 result may be subnormal. Ignoring negligible terms, the | |
78 imaginary part is +/- 1, the real part is | |
79 sin(x)*cos(x)/sinh(y)^2 = 4*sin(x)*cos(x)/exp(2y). */ | |
80 __float128 exp_2t = expq (2 * t); | |
81 | |
82 __imag__ res = copysignq (1.0Q, __imag__ x); | |
83 __real__ res = 4 * sinrx * cosrx; | |
84 __imag__ x = fabsq (__imag__ x); | |
85 __imag__ x -= t; | |
86 __real__ res /= exp_2t; | |
87 if (__imag__ x > t) | |
88 { | |
89 /* Underflow (original imaginary part of x has absolute | |
90 value > 2t). */ | |
91 __real__ res /= exp_2t; | |
92 } | |
93 else | |
94 __real__ res /= expq (2 * __imag__ x); | |
95 } | |
96 else | |
97 { | |
98 __float128 sinhix, coshix; | |
99 if (fabsq (__imag__ x) > FLT128_MIN) | |
100 { | |
101 sinhix = sinhq (__imag__ x); | |
102 coshix = coshq (__imag__ x); | |
103 } | |
104 else | |
105 { | |
106 sinhix = __imag__ x; | |
107 coshix = 1.0Q; | |
108 } | |
109 | |
110 if (fabsq (sinhix) > fabsq (cosrx) * FLT128_EPSILON) | |
111 den = cosrx * cosrx + sinhix * sinhix; | |
112 else | |
113 den = cosrx * cosrx; | |
114 __real__ res = sinrx * cosrx / den; | |
115 __imag__ res = sinhix * coshix / den; | |
116 } | |
117 } | |
118 | |
119 return res; | |
120 } |