1 /* 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, see
19 <http://www.gnu.org/licenses/>. */
20
21 #include <features.h>
22 /* Prevent math.h from defining a colliding inline */
23 #undef __USE_EXTERN_INLINES
24 #include <math.h>
25 #include "math_private.h"
26
27 static const double two52[2] =
28 {
29 4.50359962737049600000e+15, /* 0x43300000, 0x00000000 */
30 -4.50359962737049600000e+15, /* 0xC3300000, 0x00000000 */
31 };
32
33 long long int
llrint(double x)34 llrint (double x)
35 {
36 int32_t _j0;
37 u_int32_t i1, i0;
38 long long int result;
39 volatile double w;
40 double t;
41 int sx;
42
43 EXTRACT_WORDS (i0, i1, x);
44 _j0 = ((i0 >> 20) & 0x7ff) - 0x3ff;
45 sx = i0 >> 31;
46 i0 &= 0xfffff;
47 i0 |= 0x100000;
48
49 if (_j0 < 20)
50 {
51 w = two52[sx] + x;
52 t = w - two52[sx];
53 EXTRACT_WORDS (i0, i1, t);
54 _j0 = ((i0 >> 20) & 0x7ff) - 0x3ff;
55 i0 &= 0xfffff;
56 i0 |= 0x100000;
57
58 result = (_j0 < 0 ? 0 : i0 >> (20 - _j0));
59 }
60 else if (_j0 < (int32_t) (8 * sizeof (long long int)) - 1)
61 {
62 if (_j0 >= 52)
63 result = (((long long int) i0 << 32) | i1) << (_j0 - 52);
64 else
65 {
66 w = two52[sx] + x;
67 t = w - two52[sx];
68 EXTRACT_WORDS (i0, i1, t);
69 _j0 = ((i0 >> 20) & 0x7ff) - 0x3ff;
70 i0 &= 0xfffff;
71 i0 |= 0x100000;
72
73 if (_j0 == 20)
74 result = (long long int) i0;
75 else
76 result = ((long long int) i0 << (_j0 - 20)) | (i1 >> (52 - _j0));
77 }
78 }
79 else
80 {
81 /* The number is too large. It is left implementation defined
82 what happens. */
83 return (long long int) x;
84 }
85
86 return sx ? -result : result;
87 }
88
89 libm_hidden_def(llrint)
90