1/* Round double value to long long int.
2 Copyright (C) 1997-2021 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 <https://www.gnu.org/licenses/>. */
19
20#define lround __hidden_lround
21#define __lround __hidden___lround
22
23#include <fenv.h>
24#include <limits.h>
25#include <math.h>
26#include <sysdep.h>
27
28#include <math_private.h>
29#include <libm-alias-double.h>
30#include <fix-fp-int-convert-overflow.h>
31
32long long int
33__llround (double x)
34{
35 int32_t j0;
36 int64_t i0;
37 long long int result;
38 int sign;
39
40 EXTRACT_WORDS64 (i0, x);
41 j0 = ((i0 >> 52) & 0x7ff) - 0x3ff;
42 sign = i0 < 0 ? -1 : 1;
43 i0 &= UINT64_C(0xfffffffffffff);
44 i0 |= UINT64_C(0x10000000000000);
45
46 if (j0 < (int32_t) (8 * sizeof (long long int)) - 1)
47 {
48 if (j0 < 0)
49 return j0 < -1 ? 0 : sign;
50 else if (j0 >= 52)
51 result = i0 << (j0 - 52);
52 else
53 {
54 i0 += UINT64_C(0x8000000000000) >> j0;
55
56 result = i0 >> (52 - j0);
57 }
58 }
59 else
60 {
61#ifdef FE_INVALID
62 /* The number is too large. Unless it rounds to LLONG_MIN,
63 FE_INVALID must be raised and the return value is
64 unspecified. */
65 if (FIX_DBL_LLONG_CONVERT_OVERFLOW && x != (double) LLONG_MIN)
66 {
67 feraiseexcept (FE_INVALID);
68 return sign == 1 ? LLONG_MAX : LLONG_MIN;
69 }
70#endif
71 return (long long int) x;
72 }
73
74 return sign * result;
75}
76
77libm_alias_double (__llround, llround)
78
79/* long has the same width as long long on LP64 machines, so use an alias. */
80#undef lround
81#undef __lround
82#ifdef _LP64
83strong_alias (__llround, __lround)
84libm_alias_double (__lround, lround)
85#endif
86