1 /* Round argument to nearest integral value according to current rounding
2 direction.
3 Copyright (C) 1997-2022 Free Software Foundation, Inc.
4 This file is part of the GNU C Library.
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 #include <math.h>
21 #include <math_private.h>
22 #include <libm-alias-double.h>
23 #include "mathimpl.h"
24
25 long long int
__llrint(double x)26 __llrint (double x)
27 {
28 int32_t e;
29 uint32_t h, l, s;
30 long long int result;
31
32 x = __m81_u(__rint) (x);
33
34 /* We could use __fixxfdi from libgcc, but here we can take advantage of
35 the known floating point format. */
36 EXTRACT_WORDS (h, l, x);
37
38 e = ((h >> 20) & 0x7ff) - 0x3ff;
39 if (e < 0)
40 return 0;
41 s = h;
42 h &= 0xfffff;
43 h |= 0x100000;
44
45 if (e < 63)
46 {
47 if (e > 52)
48 {
49 h <<= e - 52;
50 h |= l >> (84 - e);
51 l <<= e - 52;
52 result = ((long long int) h << 32) | l;
53 }
54 else if (e > 20)
55 {
56 l >>= 52 - e;
57 l |= h << (e - 20);
58 h >>= 52 - e;
59 result = ((long long int) h << 32) | l;
60 }
61 else
62 result = h >> (20 - e);
63 if (s & 0x80000000)
64 result = -result;
65 }
66 else
67 /* The number is too large or not finite. The standard leaves it
68 undefined what to return when the number is too large to fit in a
69 `long long int'. */
70 result = -1LL;
71
72 return result;
73 }
74
75 libm_alias_double (__llrint, llrint)
76