1/* Round double value to long long int.
2 Copyright (C) 1997-2022 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
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#define lround __hidden_lround
20#define __lround __hidden___lround
21
22#include <fenv.h>
23#include <limits.h>
24#include <math.h>
25#include <sysdep.h>
26
27#include <math_private.h>
28#include <libm-alias-double.h>
29#include <fix-fp-int-convert-overflow.h>
30
31long long int
32__llround (double x)
33{
34 int32_t j0;
35 int64_t i0;
36 long long int result;
37 int sign;
38
39 EXTRACT_WORDS64 (i0, x);
40 j0 = ((i0 >> 52) & 0x7ff) - 0x3ff;
41 sign = i0 < 0 ? -1 : 1;
42 i0 &= UINT64_C(0xfffffffffffff);
43 i0 |= UINT64_C(0x10000000000000);
44
45 if (j0 < (int32_t) (8 * sizeof (long long int)) - 1)
46 {
47 if (j0 < 0)
48 return j0 < -1 ? 0 : sign;
49 else if (j0 >= 52)
50 result = i0 << (j0 - 52);
51 else
52 {
53 i0 += UINT64_C(0x8000000000000) >> j0;
54
55 result = i0 >> (52 - j0);
56 }
57 }
58 else
59 {
60#ifdef FE_INVALID
61 /* The number is too large. Unless it rounds to LLONG_MIN,
62 FE_INVALID must be raised and the return value is
63 unspecified. */
64 if (FIX_DBL_LLONG_CONVERT_OVERFLOW && x != (double) LLONG_MIN)
65 {
66 feraiseexcept (FE_INVALID);
67 return sign == 1 ? LLONG_MAX : LLONG_MIN;
68 }
69#endif
70 return (long long int) x;
71 }
72
73 return sign * result;
74}
75
76libm_alias_double (__llround, llround)
77
78/* long has the same width as long long on LP64 machines, so use an alias. */
79#undef lround
80#undef __lround
81#ifdef _LP64
82strong_alias (__llround, __lround)
83libm_alias_double (__lround, lround)
84#endif
85