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Commit | Line | Data |
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c131718c UD |
1 | /* Round argument to nearest integral value according to current rounding |
2 | direction. | |
b168057a | 3 | Copyright (C) 1997-2015 Free Software Foundation, Inc. |
c131718c UD |
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 | |
41bdb6e2 AJ |
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. | |
c131718c UD |
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 | |
41bdb6e2 | 15 | Lesser General Public License for more details. |
c131718c | 16 | |
41bdb6e2 | 17 | You should have received a copy of the GNU Lesser General Public |
59ba27a6 PE |
18 | License along with the GNU C Library; if not, see |
19 | <http://www.gnu.org/licenses/>. */ | |
c131718c UD |
20 | |
21 | #include <math.h> | |
22 | ||
1ed0291c | 23 | #include <math_private.h> |
c131718c | 24 | |
6624dbc0 | 25 | static const double two52[2] = |
c131718c UD |
26 | { |
27 | 4.50359962737049600000e+15, /* 0x43300000, 0x00000000 */ | |
28 | -4.50359962737049600000e+15, /* 0xC3300000, 0x00000000 */ | |
29 | }; | |
30 | ||
31 | ||
32 | long long int | |
dfd2257a | 33 | __llrint (double x) |
c131718c | 34 | { |
dfd2257a UD |
35 | int32_t j0; |
36 | u_int32_t i1, i0; | |
c131718c | 37 | long long int result; |
dfd2257a UD |
38 | volatile double w; |
39 | double t; | |
40 | int sx; | |
c131718c UD |
41 | |
42 | EXTRACT_WORDS (i0, i1, x); | |
c131718c | 43 | j0 = ((i0 >> 20) & 0x7ff) - 0x3ff; |
dfd2257a UD |
44 | sx = i0 >> 31; |
45 | i0 &= 0xfffff; | |
46 | i0 |= 0x100000; | |
c131718c UD |
47 | |
48 | if (j0 < 20) | |
49 | { | |
6624dbc0 UD |
50 | w = two52[sx] + x; |
51 | t = w - two52[sx]; | |
52 | EXTRACT_WORDS (i0, i1, t); | |
53 | j0 = ((i0 >> 20) & 0x7ff) - 0x3ff; | |
54 | i0 &= 0xfffff; | |
55 | i0 |= 0x100000; | |
dfd2257a | 56 | |
6624dbc0 | 57 | result = (j0 < 0 ? 0 : i0 >> (20 - j0)); |
c131718c | 58 | } |
cc3fa755 | 59 | else if (j0 < (int32_t) (8 * sizeof (long long int)) - 1) |
c131718c | 60 | { |
dfd2257a | 61 | if (j0 >= 52) |
cc3fa755 | 62 | result = (((long long int) i0 << 32) | i1) << (j0 - 52); |
c131718c UD |
63 | else |
64 | { | |
dfd2257a UD |
65 | w = two52[sx] + x; |
66 | t = w - two52[sx]; | |
67 | EXTRACT_WORDS (i0, i1, t); | |
dfd2257a | 68 | j0 = ((i0 >> 20) & 0x7ff) - 0x3ff; |
cc3fa755 UD |
69 | i0 &= 0xfffff; |
70 | i0 |= 0x100000; | |
dfd2257a | 71 | |
3eb61415 UD |
72 | if (j0 == 20) |
73 | result = (long long int) i0; | |
74 | else | |
75 | result = ((long long int) i0 << (j0 - 20)) | (i1 >> (52 - j0)); | |
c131718c UD |
76 | } |
77 | } | |
dfd2257a | 78 | else |
c131718c | 79 | { |
dfd2257a UD |
80 | /* The number is too large. It is left implementation defined |
81 | what happens. */ | |
82 | return (long long int) x; | |
c131718c | 83 | } |
c131718c | 84 | |
dfd2257a | 85 | return sx ? -result : result; |
c131718c | 86 | } |
c131718c | 87 | |
d705269e | 88 | weak_alias (__llrint, llrint) |
dfd2257a UD |
89 | #ifdef NO_LONG_DOUBLE |
90 | strong_alias (__llrint, __llrintl) | |
91 | weak_alias (__llrint, llrintl) | |
92 | #endif |