1 /* Complex sine function for float types.
2 Copyright (C) 1997-2023 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19 #include <complex.h>
20 #include <fenv.h>
21 #include <math.h>
22 #include <math_private.h>
23 #include <math-underflow.h>
24 #include <float.h>
25
26 CFLOAT
27 M_DECL_FUNC (__csin) (CFLOAT x)
28 {
29 CFLOAT retval;
30 int negate = signbit (__real__ x);
31 int rcls = fpclassify (__real__ x);
32 int icls = fpclassify (__imag__ x);
33
34 __real__ x = M_FABS (__real__ x);
35
36 if (__glibc_likely (icls >= FP_ZERO))
37 {
38 /* Imaginary part is finite. */
39 if (__glibc_likely (rcls >= FP_ZERO))
40 {
41 /* Real part is finite. */
42 const int t = (int) ((M_MAX_EXP - 1) * M_MLIT (M_LN2));
43 FLOAT sinix, cosix;
44
45 if (__glibc_likely (__real__ x > M_MIN))
46 {
47 M_SINCOS (__real__ x, &sinix, &cosix);
48 }
49 else
50 {
51 sinix = __real__ x;
52 cosix = 1;
53 }
54
55 if (negate)
56 sinix = -sinix;
57
58 if (M_FABS (__imag__ x) > t)
59 {
60 FLOAT exp_t = M_EXP (t);
61 FLOAT ix = M_FABS (__imag__ x);
62 if (signbit (__imag__ x))
63 cosix = -cosix;
64 ix -= t;
65 sinix *= exp_t / 2;
66 cosix *= exp_t / 2;
67 if (ix > t)
68 {
69 ix -= t;
70 sinix *= exp_t;
71 cosix *= exp_t;
72 }
73 if (ix > t)
74 {
75 /* Overflow (original imaginary part of x > 3t). */
76 __real__ retval = M_MAX * sinix;
77 __imag__ retval = M_MAX * cosix;
78 }
79 else
80 {
81 FLOAT exp_val = M_EXP (ix);
82 __real__ retval = exp_val * sinix;
83 __imag__ retval = exp_val * cosix;
84 }
85 }
86 else
87 {
88 __real__ retval = M_COSH (__imag__ x) * sinix;
89 __imag__ retval = M_SINH (__imag__ x) * cosix;
90 }
91
92 math_check_force_underflow_complex (retval);
93 }
94 else
95 {
96 if (icls == FP_ZERO)
97 {
98 /* Imaginary part is 0.0. */
99 __real__ retval = __real__ x - __real__ x;
100 __imag__ retval = __imag__ x;
101 }
102 else
103 {
104 __real__ retval = M_NAN;
105 __imag__ retval = M_NAN;
106
107 feraiseexcept (FE_INVALID);
108 }
109 }
110 }
111 else if (icls == FP_INFINITE)
112 {
113 /* Imaginary part is infinite. */
114 if (rcls == FP_ZERO)
115 {
116 /* Real part is 0.0. */
117 __real__ retval = M_COPYSIGN (0, negate ? -1 : 1);
118 __imag__ retval = __imag__ x;
119 }
120 else if (rcls > FP_ZERO)
121 {
122 /* Real part is finite. */
123 FLOAT sinix, cosix;
124
125 if (__glibc_likely (__real__ x > M_MIN))
126 {
127 M_SINCOS (__real__ x, &sinix, &cosix);
128 }
129 else
130 {
131 sinix = __real__ x;
132 cosix = 1;
133 }
134
135 __real__ retval = M_COPYSIGN (M_HUGE_VAL, sinix);
136 __imag__ retval = M_COPYSIGN (M_HUGE_VAL, cosix);
137
138 if (negate)
139 __real__ retval = -__real__ retval;
140 if (signbit (__imag__ x))
141 __imag__ retval = -__imag__ retval;
142 }
143 else
144 {
145 __real__ retval = __real__ x - __real__ x;
146 __imag__ retval = M_HUGE_VAL;
147 }
148 }
149 else
150 {
151 if (rcls == FP_ZERO)
152 __real__ retval = M_COPYSIGN (0, negate ? -1 : 1);
153 else
154 __real__ retval = M_NAN;
155 __imag__ retval = M_NAN;
156 }
157
158 return retval;
159 }
160
161 declare_mgen_alias (__csin, csin)