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 <fenv.h> |
20 | #include <math.h> |
21 | #include <math_private.h> |
22 | |
23 | |
24 | static double |
25 | __attribute__ ((noinline)) |
26 | invalid_fn (double x, double fn) |
27 | { |
28 | if (__rint (fn) != fn) |
29 | { |
30 | __feraiseexcept (FE_INVALID); |
31 | return __nan ("" ); |
32 | } |
33 | else if (fn > 65000.0) |
34 | return __scalbn (x, 65000); |
35 | else |
36 | return __scalbn (x,-65000); |
37 | } |
38 | |
39 | |
40 | double |
41 | __ieee754_scalb (double x, double fn) |
42 | { |
43 | if (__glibc_unlikely (isnan (x))) |
44 | return x * fn; |
45 | if (__glibc_unlikely (!isfinite (fn))) |
46 | { |
47 | if (isnan (fn) || fn > 0.0) |
48 | return x * fn; |
49 | if (x == 0.0) |
50 | return x; |
51 | return x / -fn; |
52 | } |
53 | if (__glibc_unlikely (fabs (fn) >= 0x1p31 || (double) (int) fn != fn)) |
54 | return invalid_fn (x, fn); |
55 | |
56 | return __scalbn (x, (int) fn); |
57 | } |
58 | strong_alias (__ieee754_scalb, __scalb_finite) |
59 | |