blob: b5f75c2e241b0dcde4832c0cf8720c1ad580f166 [file] [log] [blame]
lh9ed821d2023-04-07 01:36:19 -07001/* Round argument to nearest integral value according to current rounding
2 direction.
3 Copyright (C) 1997, 2004, 2006 Free Software Foundation, Inc.
4 This file is part of the GNU C Library.
5 Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
6
7 The GNU C Library is free software; you can redistribute it and/or
8 modify it under the terms of the GNU Lesser General Public
9 License as published by the Free Software Foundation; either
10 version 2.1 of the License, or (at your option) any later version.
11
12 The GNU C Library is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 Lesser General Public License for more details.
16
17 You should have received a copy of the GNU Lesser General Public
18 License along with the GNU C Library; if not, write to the Free
19 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
20 02111-1307 USA. */
21
22#include <features.h>
23/* Prevent math.h from defining a colliding inline */
24#undef __USE_EXTERN_INLINES
25#include <math.h>
26#include "math_private.h"
27
28static const double two52[2] =
29{
30 4.50359962737049600000e+15, /* 0x43300000, 0x00000000 */
31 -4.50359962737049600000e+15, /* 0xC3300000, 0x00000000 */
32};
33
34long long int
35llrint (double x)
36{
37 int32_t j0;
38 u_int32_t i1, i0;
39 long long int result;
40 volatile double w;
41 double t;
42 int sx;
43
44 EXTRACT_WORDS (i0, i1, x);
45 j0 = ((i0 >> 20) & 0x7ff) - 0x3ff;
46 sx = i0 >> 31;
47 i0 &= 0xfffff;
48 i0 |= 0x100000;
49
50 if (j0 < 20)
51 {
52 w = two52[sx] + x;
53 t = w - two52[sx];
54 EXTRACT_WORDS (i0, i1, t);
55 j0 = ((i0 >> 20) & 0x7ff) - 0x3ff;
56 i0 &= 0xfffff;
57 i0 |= 0x100000;
58
59 result = (j0 < 0 ? 0 : i0 >> (20 - j0));
60 }
61 else if (j0 < (int32_t) (8 * sizeof (long long int)) - 1)
62 {
63 if (j0 >= 52)
64 result = (((long long int) i0 << 32) | i1) << (j0 - 52);
65 else
66 {
67 w = two52[sx] + x;
68 t = w - two52[sx];
69 EXTRACT_WORDS (i0, i1, t);
70 j0 = ((i0 >> 20) & 0x7ff) - 0x3ff;
71 i0 &= 0xfffff;
72 i0 |= 0x100000;
73
74 if (j0 == 20)
75 result = (long long int) i0;
76 else
77 result = ((long long int) i0 << (j0 - 20)) | (i1 >> (52 - j0));
78 }
79 }
80 else
81 {
82 /* The number is too large. It is left implementation defined
83 what happens. */
84 return (long long int) x;
85 }
86
87 return sx ? -result : result;
88}
89
90libm_hidden_def(llrint)