1/* Round double value to long long int.
2 Copyright (C) 1997-2016 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4 Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
5
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
10
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
15
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, see
18 <http://www.gnu.org/licenses/>. */
19
20#define lround __hidden_lround
21#define __lround __hidden___lround
22
23#include <math.h>
24#include <sysdep.h>
25
26#include <math_private.h>
27
28
29long long int
30__llround (double x)
31{
32 int32_t j0;
33 int64_t i0;
34 long long int result;
35 int sign;
36
37 EXTRACT_WORDS64 (i0, x);
38 j0 = ((i0 >> 52) & 0x7ff) - 0x3ff;
39 sign = i0 < 0 ? -1 : 1;
40 i0 &= UINT64_C(0xfffffffffffff);
41 i0 |= UINT64_C(0x10000000000000);
42
43 if (j0 < (int32_t) (8 * sizeof (long long int)) - 1)
44 {
45 if (j0 < 0)
46 return j0 < -1 ? 0 : sign;
47 else if (j0 >= 52)
48 result = i0 << (j0 - 52);
49 else
50 {
51 i0 += UINT64_C(0x8000000000000) >> j0;
52
53 result = i0 >> (52 - j0);
54 }
55 }
56 else
57 {
58 /* The number is too large. It is left implementation defined
59 what happens. */
60 return (long long int) x;
61 }
62
63 return sign * result;
64}
65
66weak_alias (__llround, llround)
67#ifdef NO_LONG_DOUBLE
68strong_alias (__llround, __llroundl)
69weak_alias (__llround, llroundl)
70#endif
71
72/* long has the same width as long long on LP64 machines, so use an alias. */
73#undef lround
74#undef __lround
75#ifdef _LP64
76strong_alias (__llround, __lround)
77weak_alias (__llround, lround)
78# ifdef NO_LONG_DOUBLE
79strong_alias (__llround, __lroundl)
80weak_alias (__llround, lroundl)
81# endif
82#endif
83