aboutsummaryrefslogtreecommitdiff
path: root/math/e_scalb.c
blob: d315d57681f863ce13cc96f0b41362343b24013d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
/* Copyright (C) 2011-2014 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Ulrich Drepper <drepper@gmail.com>, 2011.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <http://www.gnu.org/licenses/>.  */

#include <fenv.h>
#include <math.h>
#include <math_private.h>


static double
__attribute__ ((noinline))
invalid_fn (double x, double fn)
{
  if (__rint (fn) != fn)
    {
      __feraiseexcept (FE_INVALID);
      return __nan ("");
    }
  else if (fn > 65000.0)
    return __scalbn (x, 65000);
  else
    return __scalbn (x,-65000);
}


double
__ieee754_scalb (double x, double fn)
{
  if (__glibc_unlikely (__isnan (x)))
    return x * fn;
  if (__glibc_unlikely (!__finite (fn)))
    {
      if (__isnan (fn) || fn > 0.0)
	return x * fn;
      if (x == 0.0)
	return x;
      return x / -fn;
    }
  if (__glibc_unlikely (fabs (fn) >= 0x1p31 || (double) (int) fn != fn))
    return invalid_fn (x, fn);

  return __scalbn (x, (int) fn);
}
strong_alias (__ieee754_scalb, __scalb_finite)