]>
Commit | Line | Data |
---|---|---|
fb146a76 UD |
1 | /* Round to long int long double floating-point values. |
2 | IBM extended format long double version. | |
2b778ceb | 3 | Copyright (C) 2006-2021 Free Software Foundation, Inc. |
fb146a76 UD |
4 | This file is part of the GNU C Library. |
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 | |
59ba27a6 | 17 | License along with the GNU C Library; if not, see |
5a82c748 | 18 | <https://www.gnu.org/licenses/>. */ |
fb146a76 | 19 | |
f964490f | 20 | #include <math.h> |
4a3d3999 | 21 | #include <fenv.h> |
0d13dfa1 | 22 | #include <math_private.h> |
f964490f | 23 | #include <math_ldbl_opt.h> |
fb146a76 UD |
24 | #include <float.h> |
25 | #include <ieee754.h> | |
f964490f | 26 | |
fb146a76 UD |
27 | long |
28 | __lroundl (long double x) | |
f964490f | 29 | { |
fb146a76 UD |
30 | double xh, xl; |
31 | long res, hi, lo; | |
32 | ||
33 | ldbl_unpack (x, &xh, &xl); | |
34 | ||
35 | /* Limit the range of values handled by the conversion to long. | |
36 | We do this because we aren't sure whether that conversion properly | |
37 | raises FE_INVALID. */ | |
38 | if ( | |
39 | #if __LONG_MAX__ == 2147483647 | |
40 | __builtin_expect | |
41 | ((__builtin_fabs (xh) <= (double) __LONG_MAX__ + 2), 1) | |
42 | #else | |
43 | __builtin_expect | |
44 | ((__builtin_fabs (xh) <= -(double) (-__LONG_MAX__ - 1)), 1) | |
45 | #endif | |
46 | #if !defined (FE_INVALID) | |
47 | || 1 | |
48 | #endif | |
49 | ) | |
50 | { | |
51 | #if __LONG_MAX__ == 2147483647 | |
52 | long long llhi = (long long) xh; | |
53 | if (llhi != (long) llhi) | |
54 | hi = llhi < 0 ? -__LONG_MAX__ - 1 : __LONG_MAX__; | |
55 | else | |
56 | hi = llhi; | |
57 | xh -= hi; | |
58 | #else | |
a1ffb40e | 59 | if (__glibc_unlikely ((xh == -(double) (-__LONG_MAX__ - 1)))) |
fb146a76 UD |
60 | { |
61 | /* When XH is 9223372036854775808.0, converting to long long will | |
62 | overflow, resulting in an invalid operation. However, XL might | |
63 | be negative and of sufficient magnitude that the overall long | |
64 | double is in fact in range. Avoid raising an exception. In any | |
65 | case we need to convert this value specially, because | |
66 | the converted value is not exactly represented as a double | |
67 | thus subtracting HI from XH suffers rounding error. */ | |
68 | hi = __LONG_MAX__; | |
69 | xh = 1.0; | |
70 | } | |
71 | else | |
72 | { | |
73 | hi = (long) xh; | |
74 | xh -= hi; | |
75 | } | |
76 | #endif | |
77 | ldbl_canonicalize (&xh, &xl); | |
78 | ||
79 | lo = (long) xh; | |
80 | ||
81 | /* Peg at max/min values, assuming that the above conversions do so. | |
82 | Strictly speaking, we can return anything for values that overflow, | |
83 | but this is more useful. */ | |
12727488 | 84 | res = (long int) ((unsigned long int) hi + (unsigned long int) lo); |
fb146a76 UD |
85 | |
86 | /* This is just sign(hi) == sign(lo) && sign(res) != sign(hi). */ | |
a1ffb40e | 87 | if (__glibc_unlikely (((~(hi ^ lo) & (res ^ hi)) < 0))) |
fb146a76 UD |
88 | goto overflow; |
89 | ||
90 | xh -= lo; | |
91 | ldbl_canonicalize (&xh, &xl); | |
92 | ||
93 | hi = res; | |
94 | if (xh > 0.5) | |
95 | { | |
12727488 | 96 | res += 1UL; |
fb146a76 UD |
97 | } |
98 | else if (xh == 0.5) | |
99 | { | |
100 | if (xl > 0.0 || (xl == 0.0 && res >= 0)) | |
12727488 | 101 | res += 1UL; |
fb146a76 UD |
102 | } |
103 | else if (-xh > 0.5) | |
104 | { | |
12727488 | 105 | res -= 1UL; |
fb146a76 UD |
106 | } |
107 | else if (-xh == 0.5) | |
108 | { | |
109 | if (xl < 0.0 || (xl == 0.0 && res <= 0)) | |
12727488 | 110 | res -= 1UL; |
fb146a76 UD |
111 | } |
112 | ||
a1ffb40e | 113 | if (__glibc_unlikely (((~(hi ^ (res - hi)) & (res ^ hi)) < 0))) |
fb146a76 UD |
114 | goto overflow; |
115 | ||
116 | return res; | |
117 | } | |
118 | else | |
119 | { | |
120 | if (xh > 0.0) | |
121 | hi = __LONG_MAX__; | |
122 | else if (xh < 0.0) | |
123 | hi = -__LONG_MAX__ - 1; | |
124 | else | |
125 | /* Nan */ | |
126 | hi = 0; | |
127 | } | |
128 | ||
129 | overflow: | |
130 | #ifdef FE_INVALID | |
131 | feraiseexcept (FE_INVALID); | |
132 | #endif | |
133 | return hi; | |
f964490f | 134 | } |
fb146a76 | 135 | |
f964490f | 136 | long_double_symbol (libm, __lroundl, lroundl); |