1 /* Copyright (C) 2011-2016 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3 Contributed by Ulrich Drepper <drepper@gmail.com>, 2011.
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 <http://www.gnu.org/licenses/>. */
18
19 #include <math.h>
20 #include "math_private.h"
21
22 /* wrapper exp2(x) */
23 double
exp2(double x)24 exp2 (double x)
25 {
26 #if defined(__UCLIBC_HAS_FENV__)
27 double z = pow(2.0, x);
28 if (__builtin_expect (!isfinite (z) || z == 0, 0)
29 && isfinite (x) && _LIB_VERSION != _IEEE_)
30 /* exp2 overflow: 44, exp2 underflow: 45 */
31 return __kernel_standard (x, x, 44 + !!signbit (x));
32
33 return z;
34 #else
35 return pow(2.0, x);
36 #endif
37 }
38 libm_hidden_def(exp2)
39