1 | /* Round long double to integer away from zero. |
2 | Copyright (C) 1997-2017 Free Software Foundation, Inc. |
3 | This file is part of the GNU C Library. |
4 | Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997. |
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 | <http://www.gnu.org/licenses/>. */ |
19 | |
20 | #include <math.h> |
21 | |
22 | #include <math_private.h> |
23 | |
24 | |
25 | long double |
26 | __roundl (long double x) |
27 | { |
28 | int32_t j0; |
29 | u_int32_t se, i1, i0; |
30 | |
31 | GET_LDOUBLE_WORDS (se, i0, i1, x); |
32 | j0 = (se & 0x7fff) - 0x3fff; |
33 | if (j0 < 31) |
34 | { |
35 | if (j0 < 0) |
36 | { |
37 | se &= 0x8000; |
38 | i0 = i1 = 0; |
39 | if (j0 == -1) |
40 | { |
41 | se |= 0x3fff; |
42 | i0 = 0x80000000; |
43 | } |
44 | } |
45 | else |
46 | { |
47 | u_int32_t i = 0x7fffffff >> j0; |
48 | if (((i0 & i) | i1) == 0) |
49 | /* X is integral. */ |
50 | return x; |
51 | |
52 | u_int32_t j = i0 + (0x40000000 >> j0); |
53 | if (j < i0) |
54 | se += 1; |
55 | i0 = (j & ~i) | 0x80000000; |
56 | i1 = 0; |
57 | } |
58 | } |
59 | else if (j0 > 62) |
60 | { |
61 | if (j0 == 0x4000) |
62 | /* Inf or NaN. */ |
63 | return x + x; |
64 | else |
65 | return x; |
66 | } |
67 | else |
68 | { |
69 | u_int32_t i = 0xffffffff >> (j0 - 31); |
70 | if ((i1 & i) == 0) |
71 | /* X is integral. */ |
72 | return x; |
73 | |
74 | u_int32_t j = i1 + (1 << (62 - j0)); |
75 | if (j < i1) |
76 | { |
77 | u_int32_t k = i0 + 1; |
78 | if (k < i0) |
79 | { |
80 | se += 1; |
81 | k |= 0x80000000; |
82 | } |
83 | i0 = k; |
84 | } |
85 | i1 = j; |
86 | i1 &= ~i; |
87 | } |
88 | |
89 | SET_LDOUBLE_WORDS (x, se, i0, i1); |
90 | return x; |
91 | } |
92 | weak_alias (__roundl, roundl) |
93 | |