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
23 /* wrapper pow */
24 double
pow(double x,double y)25 pow (double x, double y)
26 {
27 #if defined(__UCLIBC_HAS_FENV__)
28 double z = __ieee754_pow (x, y);
29 if (__builtin_expect (!isfinite (z), 0))
30 {
31 if (_LIB_VERSION != _IEEE_)
32 {
33 if (isnan (x))
34 {
35 if (y == 0.0)
36 /* pow(NaN,0.0) */
37 return __kernel_standard (x, y, 42);
38 }
39 else if (isfinite (x) && isfinite (y))
40 {
41 if (isnan (z))
42 /* pow neg**non-int */
43 return __kernel_standard (x, y, 24);
44 else if (x == 0.0 && y < 0.0)
45 {
46 if (signbit (x) && signbit (z))
47 /* pow(-0.0,negative) */
48 return __kernel_standard (x, y, 23);
49 else
50 /* pow(+0.0,negative) */
51 return __kernel_standard (x, y, 43);
52 }
53 else
54 /* pow overflow */
55 return __kernel_standard (x, y, 21);
56 }
57 }
58 }
59 else if (__builtin_expect (z == 0.0, 0) && isfinite (x) && isfinite (y)
60 && _LIB_VERSION != _IEEE_)
61 {
62 if (x == 0.0)
63 {
64 if (y == 0.0)
65 /* pow(0.0,0.0) */
66 return __kernel_standard (x, y, 20);
67 }
68 else
69 /* pow underflow */
70 return __kernel_standard (x, y, 22);
71 }
72
73 return z;
74 #else
75 return __ieee754_pow (x, y);
76 #endif
77 }
78 libm_hidden_def(pow)
79