1/* Round long double value to long int.
2 Copyright (C) 1997-2023 Free Software Foundation, Inc.
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 <https://www.gnu.org/licenses/>. */
18
19#include <fenv.h>
20#include <limits.h>
21#include <math.h>
22
23#include <math_private.h>
24#include <libm-alias-ldouble.h>
25
26
27long int
28__lroundl (long double x)
29{
30 int32_t j0;
31 uint32_t se, i1, i0;
32 long int result;
33 int sign;
34
35 GET_LDOUBLE_WORDS (se, i0, i1, x);
36 j0 = (se & 0x7fff) - 0x3fff;
37 sign = (se & 0x8000) != 0 ? -1 : 1;
38
39 if (j0 < 31)
40 {
41 if (j0 < 0)
42 return j0 < -1 ? 0 : sign;
43 else
44 {
45 uint32_t j = i0 + (0x40000000 >> j0);
46 if (j < i0)
47 {
48 j >>= 1;
49 j |= 0x80000000;
50 ++j0;
51 }
52
53 result = j >> (31 - j0);
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
61 }
62 }
63 else if (j0 < (int32_t) (8 * sizeof (long int)) - 1)
64 {
65 if (j0 >= 63)
66 result = ((long int) i0 << (j0 - 31)) | (i1 << (j0 - 63));
67 else
68 {
69 uint32_t j = i1 + (0x80000000 >> (j0 - 31));
70 unsigned long int ures = i0;
71
72 if (j < i1)
73 ++ures;
74
75 if (j0 == 31)
76 result = ures;
77 else
78 {
79 result = (ures << (j0 - 31)) | (j >> (63 - j0));
80#ifdef FE_INVALID
81 if (sizeof (long int) == 8
82 && sign == 1
83 && result == LONG_MIN)
84 /* Rounding brought the value out of range. */
85 feraiseexcept (FE_INVALID);
86#endif
87 }
88 }
89 }
90 else
91 {
92 /* The number is too large. Unless it rounds to LONG_MIN,
93 FE_INVALID must be raised and the return value is
94 unspecified. */
95#ifdef FE_INVALID
96 if (sizeof (long int) == 4
97 && x <= (long double) LONG_MIN - 0.5L)
98 {
99 /* If truncation produces LONG_MIN, the cast will not raise
100 the exception, but may raise "inexact". */
101 feraiseexcept (FE_INVALID);
102 return LONG_MIN;
103 }
104#endif
105 return (long int) x;
106 }
107
108 return sign * result;
109}
110
111libm_alias_ldouble (__lround, lround)
112