1 | /* Round long double to integer away from zero. |
2 | Copyright (C) 1997-2016 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 | static const long double huge = 1.0e4930L; |
26 | |
27 | |
28 | long double |
29 | __roundl (long double x) |
30 | { |
31 | int32_t j0; |
32 | u_int32_t se, i1, i0; |
33 | |
34 | GET_LDOUBLE_WORDS (se, i0, i1, x); |
35 | j0 = (se & 0x7fff) - 0x3fff; |
36 | if (j0 < 31) |
37 | { |
38 | if (j0 < 0) |
39 | { |
40 | math_force_eval (huge + x); |
41 | se &= 0x8000; |
42 | i0 = i1 = 0; |
43 | if (j0 == -1) |
44 | { |
45 | se |= 0x3fff; |
46 | i0 = 0x80000000; |
47 | } |
48 | } |
49 | else |
50 | { |
51 | u_int32_t i = 0x7fffffff >> j0; |
52 | if (((i0 & i) | i1) == 0) |
53 | /* X is integral. */ |
54 | return x; |
55 | |
56 | /* Raise inexact if x != 0. */ |
57 | math_force_eval (huge + x); |
58 | u_int32_t j = i0 + (0x40000000 >> j0); |
59 | if (j < i0) |
60 | se += 1; |
61 | i0 = (j & ~i) | 0x80000000; |
62 | i1 = 0; |
63 | } |
64 | } |
65 | else if (j0 > 62) |
66 | { |
67 | if (j0 == 0x4000) |
68 | /* Inf or NaN. */ |
69 | return x + x; |
70 | else |
71 | return x; |
72 | } |
73 | else |
74 | { |
75 | u_int32_t i = 0xffffffff >> (j0 - 31); |
76 | if ((i1 & i) == 0) |
77 | /* X is integral. */ |
78 | return x; |
79 | |
80 | math_force_eval (huge + x); |
81 | /* Raise inexact if x != 0. */ |
82 | u_int32_t j = i1 + (1 << (62 - j0)); |
83 | if (j < i1) |
84 | { |
85 | u_int32_t k = i0 + 1; |
86 | if (k < i0) |
87 | { |
88 | se += 1; |
89 | k |= 0x80000000; |
90 | } |
91 | i0 = k; |
92 | } |
93 | i1 = j; |
94 | i1 &= ~i; |
95 | } |
96 | |
97 | SET_LDOUBLE_WORDS (x, se, i0, i1); |
98 | return x; |
99 | } |
100 | weak_alias (__roundl, roundl) |
101 | |