1/* Copyright (C) 2011-2020 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 <https://www.gnu.org/licenses/>. */
18
19#include <math.h>
20#include <math_private.h>
21#include <libm-alias-finite.h>
22
23static double
24__attribute__ ((noinline))
25invalid_fn (double x, double fn)
26{
27 if (rint (fn) != fn)
28 return (fn - fn) / (fn - fn);
29 else if (fn > 65000.0)
30 return __scalbn (x, 65000);
31 else
32 return __scalbn (x,-65000);
33}
34
35
36double
37__ieee754_scalb (double x, double fn)
38{
39 if (__glibc_unlikely (isnan (x)))
40 return x * fn;
41 if (__glibc_unlikely (!isfinite (fn)))
42 {
43 if (isnan (fn) || fn > 0.0)
44 return x * fn;
45 if (x == 0.0)
46 return x;
47 return x / -fn;
48 }
49 if (__glibc_unlikely (fabs (fn) >= 0x1p31 || (double) (int) fn != fn))
50 return invalid_fn (x, fn);
51
52 return __scalbn (x, (int) fn);
53}
54libm_alias_finite (__ieee754_scalb, __scalb)
55