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b75bc69c | 1 | /* Round double value to long int. |
04277e02 | 2 | Copyright (C) 1997-2019 Free Software Foundation, Inc. |
b75bc69c JM |
3 | This file is part of the GNU C Library. |
4 | ||
5 | The GNU C Library is free software; you can redistribute it and/or | |
6 | modify it under the terms of the GNU Lesser General Public | |
7 | License as published by the Free Software Foundation; either | |
8 | version 2.1 of the License, or (at your option) any later version. | |
9 | ||
10 | The GNU C Library is distributed in the hope that it will be useful, | |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
13 | Lesser General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU Lesser General Public | |
16 | License along with the GNU C Library; if not, see | |
17 | <http://www.gnu.org/licenses/>. */ | |
18 | ||
8afdb7ac JM |
19 | #include <fenv.h> |
20 | #include <limits.h> | |
b75bc69c JM |
21 | #include <math.h> |
22 | ||
23 | #include <math_private.h> | |
a1132b5e | 24 | #include <libm-alias-double.h> |
b75bc69c JM |
25 | |
26 | /* For LP64, lround is an alias for llround. */ | |
27 | #ifndef _LP64 | |
28 | ||
29 | long int | |
30 | __lround (double x) | |
31 | { | |
32 | int32_t j0; | |
33 | int64_t i0; | |
34 | long int result; | |
35 | int sign; | |
36 | ||
37 | EXTRACT_WORDS64 (i0, x); | |
38 | j0 = ((i0 >> 52) & 0x7ff) - 0x3ff; | |
39 | sign = i0 < 0 ? -1 : 1; | |
40 | i0 &= UINT64_C(0xfffffffffffff); | |
41 | i0 |= UINT64_C(0x10000000000000); | |
42 | ||
43 | if (j0 < (int32_t) (8 * sizeof (long int)) - 1) | |
44 | { | |
45 | if (j0 < 0) | |
46 | return j0 < -1 ? 0 : sign; | |
47 | else if (j0 >= 52) | |
48 | result = i0 << (j0 - 52); | |
49 | else | |
50 | { | |
51 | i0 += UINT64_C(0x8000000000000) >> j0; | |
52 | ||
53 | result = i0 >> (52 - j0); | |
8afdb7ac JM |
54 | #ifdef FE_INVALID |
55 | if (sizeof (long int) == 4 | |
56 | && sign == 1 | |
57 | && result == LONG_MIN) | |
58 | /* Rounding brought the value out of range. */ | |
59 | feraiseexcept (FE_INVALID); | |
60 | #endif | |
b75bc69c JM |
61 | } |
62 | } | |
63 | else | |
64 | { | |
8afdb7ac JM |
65 | /* The number is too large. Unless it rounds to LONG_MIN, |
66 | FE_INVALID must be raised and the return value is | |
67 | unspecified. */ | |
68 | #ifdef FE_INVALID | |
69 | if (sizeof (long int) == 4 | |
70 | && x <= (double) LONG_MIN - 0.5) | |
71 | { | |
72 | /* If truncation produces LONG_MIN, the cast will not raise | |
73 | the exception, but may raise "inexact". */ | |
74 | feraiseexcept (FE_INVALID); | |
75 | return LONG_MIN; | |
76 | } | |
77 | #endif | |
b75bc69c JM |
78 | return (long int) x; |
79 | } | |
80 | ||
81 | return sign * result; | |
82 | } | |
83 | ||
a1132b5e | 84 | libm_alias_double (__lround, lround) |
b75bc69c JM |
85 | |
86 | #endif |