1 | /* Return value of complex exponential function for a float type. |
2 | Copyright (C) 1997-2022 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 (__cexp) (CFLOAT x) |
28 | { |
29 | CFLOAT retval; |
30 | int rcls = fpclassify (__real__ x); |
31 | int icls = fpclassify (__imag__ x); |
32 | |
33 | if (__glibc_likely (rcls >= FP_ZERO)) |
34 | { |
35 | /* Real part is finite. */ |
36 | if (__glibc_likely (icls >= FP_ZERO)) |
37 | { |
38 | /* Imaginary part is finite. */ |
39 | const int t = (int) ((M_MAX_EXP - 1) * M_MLIT (M_LN2)); |
40 | FLOAT sinix, cosix; |
41 | |
42 | if (__glibc_likely (M_FABS (__imag__ x) > M_MIN)) |
43 | { |
44 | M_SINCOS (__imag__ x, &sinix, &cosix); |
45 | } |
46 | else |
47 | { |
48 | sinix = __imag__ x; |
49 | cosix = 1; |
50 | } |
51 | |
52 | if (__real__ x > t) |
53 | { |
54 | FLOAT exp_t = M_EXP (t); |
55 | __real__ x -= t; |
56 | sinix *= exp_t; |
57 | cosix *= exp_t; |
58 | if (__real__ x > t) |
59 | { |
60 | __real__ x -= t; |
61 | sinix *= exp_t; |
62 | cosix *= exp_t; |
63 | } |
64 | } |
65 | if (__real__ x > t) |
66 | { |
67 | /* Overflow (original real part of x > 3t). */ |
68 | __real__ retval = M_MAX * cosix; |
69 | __imag__ retval = M_MAX * sinix; |
70 | } |
71 | else |
72 | { |
73 | FLOAT exp_val = M_EXP (__real__ x); |
74 | __real__ retval = exp_val * cosix; |
75 | __imag__ retval = exp_val * sinix; |
76 | } |
77 | math_check_force_underflow_complex (retval); |
78 | } |
79 | else |
80 | { |
81 | /* If the imaginary part is +-inf or NaN and the real part |
82 | is not +-inf the result is NaN + iNaN. */ |
83 | __real__ retval = M_NAN; |
84 | __imag__ retval = M_NAN; |
85 | |
86 | feraiseexcept (FE_INVALID); |
87 | } |
88 | } |
89 | else if (__glibc_likely (rcls == FP_INFINITE)) |
90 | { |
91 | /* Real part is infinite. */ |
92 | if (__glibc_likely (icls >= FP_ZERO)) |
93 | { |
94 | /* Imaginary part is finite. */ |
95 | FLOAT value = signbit (__real__ x) ? 0 : M_HUGE_VAL; |
96 | |
97 | if (icls == FP_ZERO) |
98 | { |
99 | /* Imaginary part is 0.0. */ |
100 | __real__ retval = value; |
101 | __imag__ retval = __imag__ x; |
102 | } |
103 | else |
104 | { |
105 | FLOAT sinix, cosix; |
106 | |
107 | if (__glibc_likely (M_FABS (__imag__ x) > M_MIN)) |
108 | { |
109 | M_SINCOS (__imag__ x, &sinix, &cosix); |
110 | } |
111 | else |
112 | { |
113 | sinix = __imag__ x; |
114 | cosix = 1; |
115 | } |
116 | |
117 | __real__ retval = M_COPYSIGN (value, cosix); |
118 | __imag__ retval = M_COPYSIGN (value, sinix); |
119 | } |
120 | } |
121 | else if (signbit (__real__ x) == 0) |
122 | { |
123 | __real__ retval = M_HUGE_VAL; |
124 | __imag__ retval = __imag__ x - __imag__ x; |
125 | } |
126 | else |
127 | { |
128 | __real__ retval = 0; |
129 | __imag__ retval = M_COPYSIGN (0, __imag__ x); |
130 | } |
131 | } |
132 | else |
133 | { |
134 | /* If the real part is NaN the result is NaN + iNaN unless the |
135 | imaginary part is zero. */ |
136 | __real__ retval = M_NAN; |
137 | if (icls == FP_ZERO) |
138 | __imag__ retval = __imag__ x; |
139 | else |
140 | { |
141 | __imag__ retval = M_NAN; |
142 | |
143 | if (rcls != FP_NAN || icls != FP_NAN) |
144 | feraiseexcept (FE_INVALID); |
145 | } |
146 | } |
147 | |
148 | return retval; |
149 | } |
150 | declare_mgen_alias (__cexp, cexp) |
151 | |