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
26CFLOAT
27M_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}
150declare_mgen_alias (__cexp, cexp)
151

source code of glibc/math/s_cexp_template.c