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c131718c UD |
1 | /* Round argument to nearest integral value according to current rounding |
2 | direction. | |
3 | Copyright (C) 1997 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 | |
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 AJ |
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. */ | |
c131718c UD |
21 | |
22 | #include <math.h> | |
23 | ||
24 | #include "math_private.h" | |
25 | ||
dfd2257a | 26 | static const double two52[2] = |
c131718c UD |
27 | { |
28 | 4.50359962737049600000e+15, /* 0x43300000, 0x00000000 */ | |
29 | -4.50359962737049600000e+15, /* 0xC3300000, 0x00000000 */ | |
30 | }; | |
31 | ||
32 | ||
33 | long int | |
dfd2257a | 34 | __lrint (double x) |
c131718c | 35 | { |
dfd2257a | 36 | int32_t j0; |
6973fc01 | 37 | u_int32_t i0,i1; |
dfd2257a UD |
38 | volatile double w; |
39 | double t; | |
c131718c | 40 | long int result; |
dfd2257a | 41 | int sx; |
c131718c UD |
42 | |
43 | EXTRACT_WORDS (i0, i1, x); | |
c131718c | 44 | j0 = ((i0 >> 20) & 0x7ff) - 0x3ff; |
dfd2257a UD |
45 | sx = i0 >> 31; |
46 | i0 &= 0xfffff; | |
47 | i0 |= 0x100000; | |
c131718c UD |
48 | |
49 | if (j0 < 20) | |
50 | { | |
dfd2257a UD |
51 | if (j0 < -1) |
52 | return 0; | |
c131718c UD |
53 | else |
54 | { | |
dfd2257a UD |
55 | w = two52[sx] + x; |
56 | t = w - two52[sx]; | |
57 | EXTRACT_WORDS (i0, i1, t); | |
dfd2257a | 58 | j0 = ((i0 >> 20) & 0x7ff) - 0x3ff; |
6973fc01 UD |
59 | i0 &= 0xfffff; |
60 | i0 |= 0x100000; | |
dfd2257a UD |
61 | |
62 | result = i0 >> (20 - j0); | |
c131718c UD |
63 | } |
64 | } | |
cc3fa755 | 65 | else if (j0 < (int32_t) (8 * sizeof (long int)) - 1) |
c131718c | 66 | { |
dfd2257a UD |
67 | if (j0 >= 52) |
68 | result = ((long int) i0 << (j0 - 20)) | (i1 << (j0 - 52)); | |
c131718c UD |
69 | else |
70 | { | |
dfd2257a UD |
71 | w = two52[sx] + x; |
72 | t = w - two52[sx]; | |
73 | EXTRACT_WORDS (i0, i1, t); | |
dfd2257a | 74 | j0 = ((i0 >> 20) & 0x7ff) - 0x3ff; |
6973fc01 UD |
75 | i0 &= 0xfffff; |
76 | i0 |= 0x100000; | |
dfd2257a | 77 | |
cc3fa755 | 78 | result = ((long int) i0 << (j0 - 20)) | (i1 >> (52 - j0)); |
c131718c UD |
79 | } |
80 | } | |
dfd2257a | 81 | else |
c131718c | 82 | { |
dfd2257a UD |
83 | /* The number is too large. It is left implementation defined |
84 | what happens. */ | |
85 | return (long int) x; | |
c131718c | 86 | } |
c131718c | 87 | |
dfd2257a | 88 | return sx ? -result : result; |
c131718c | 89 | } |
c131718c | 90 | |
d705269e | 91 | weak_alias (__lrint, lrint) |
dfd2257a UD |
92 | #ifdef NO_LONG_DOUBLE |
93 | strong_alias (__lrint, __lrintl) | |
94 | weak_alias (__lrint, lrintl) | |
95 | #endif |