1 | /* Round argument to nearest integral value according to current rounding |
2 | direction. |
3 | Copyright (C) 1997-2022 Free Software Foundation, Inc. |
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 |
17 | License along with the GNU C Library; if not, see |
18 | <https://www.gnu.org/licenses/>. */ |
19 | |
20 | #include <fenv.h> |
21 | #include <limits.h> |
22 | #include <math.h> |
23 | |
24 | #include <math_private.h> |
25 | #include <libm-alias-ldouble.h> |
26 | |
27 | static const long double two63[2] = |
28 | { |
29 | 9.223372036854775808000000e+18, /* 0x403E, 0x00000000, 0x00000000 */ |
30 | -9.223372036854775808000000e+18 /* 0xC03E, 0x00000000, 0x00000000 */ |
31 | }; |
32 | |
33 | |
34 | long int |
35 | __lrintl (long double x) |
36 | { |
37 | int32_t se,j0; |
38 | uint32_t i0, i1; |
39 | long int result; |
40 | long double w; |
41 | long double t; |
42 | int sx; |
43 | |
44 | GET_LDOUBLE_WORDS (se, i0, i1, x); |
45 | |
46 | sx = (se >> 15) & 1; |
47 | j0 = (se & 0x7fff) - 0x3fff; |
48 | |
49 | if (j0 < 31) |
50 | { |
51 | #if defined FE_INVALID || defined FE_INEXACT |
52 | /* X < LONG_MAX + 1 implied by J0 < 31. */ |
53 | if (sizeof (long int) == 4 |
54 | && x > (long double) LONG_MAX) |
55 | { |
56 | /* In the event of overflow we must raise the "invalid" |
57 | exception, but not "inexact". */ |
58 | t = __nearbyintl (x: x); |
59 | feraiseexcept (excepts: t == LONG_MAX ? FE_INEXACT : FE_INVALID); |
60 | } |
61 | else |
62 | #endif |
63 | { |
64 | w = two63[sx] + x; |
65 | t = w - two63[sx]; |
66 | } |
67 | GET_LDOUBLE_WORDS (se, i0, i1, t); |
68 | j0 = (se & 0x7fff) - 0x3fff; |
69 | |
70 | result = (j0 < 0 ? 0 : i0 >> (31 - j0)); |
71 | } |
72 | else if (j0 < (int32_t) (8 * sizeof (long int)) - 1) |
73 | { |
74 | if (j0 >= 63) |
75 | result = ((long int) i0 << (j0 - 31)) | (i1 << (j0 - 63)); |
76 | else |
77 | { |
78 | #if defined FE_INVALID || defined FE_INEXACT |
79 | /* X < LONG_MAX + 1 implied by J0 < 63. */ |
80 | if (sizeof (long int) == 8 |
81 | && x > (long double) LONG_MAX) |
82 | { |
83 | /* In the event of overflow we must raise the "invalid" |
84 | exception, but not "inexact". */ |
85 | t = __nearbyintl (x: x); |
86 | feraiseexcept (excepts: t == LONG_MAX ? FE_INEXACT : FE_INVALID); |
87 | } |
88 | else |
89 | #endif |
90 | { |
91 | w = two63[sx] + x; |
92 | t = w - two63[sx]; |
93 | } |
94 | GET_LDOUBLE_WORDS (se, i0, i1, t); |
95 | j0 = (se & 0x7fff) - 0x3fff; |
96 | |
97 | if (j0 == 31) |
98 | result = (long int) i0; |
99 | else |
100 | result = ((long int) i0 << (j0 - 31)) | (i1 >> (63 - j0)); |
101 | } |
102 | } |
103 | else |
104 | { |
105 | /* The number is too large. Unless it rounds to LONG_MIN, |
106 | FE_INVALID must be raised and the return value is |
107 | unspecified. */ |
108 | #if defined FE_INVALID || defined FE_INEXACT |
109 | if (sizeof (long int) == 4 |
110 | && x < (long double) LONG_MIN |
111 | && x > (long double) LONG_MIN - 1.0L) |
112 | { |
113 | /* If truncation produces LONG_MIN, the cast will not raise |
114 | the exception, but may raise "inexact". */ |
115 | t = __nearbyintl (x: x); |
116 | feraiseexcept (excepts: t == LONG_MIN ? FE_INEXACT : FE_INVALID); |
117 | return LONG_MIN; |
118 | } |
119 | #endif |
120 | return (long int) x; |
121 | } |
122 | |
123 | return sx ? -result : result; |
124 | } |
125 | |
126 | libm_alias_ldouble (__lrint, lrint) |
127 | |