1/* Round long double value to long int.
2 Copyright (C) 1997-2020 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 <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
28long int
29__lroundl (long double x)
30{
31 int32_t j0;
32 uint32_t se, i1, i0;
33 long int result;
34 int sign;
35
36 GET_LDOUBLE_WORDS (se, i0, i1, x);
37 j0 = (se & 0x7fff) - 0x3fff;
38 sign = (se & 0x8000) != 0 ? -1 : 1;
39
40 if (j0 < 31)
41 {
42 if (j0 < 0)
43 return j0 < -1 ? 0 : sign;
44 else
45 {
46 uint32_t j = i0 + (0x40000000 >> j0);
47 if (j < i0)
48 {
49 j >>= 1;
50 j |= 0x80000000;
51 ++j0;
52 }
53
54 result = j >> (31 - j0);
55#ifdef FE_INVALID
56 if (sizeof (long int) == 4
57 && sign == 1
58 && result == LONG_MIN)
59 /* Rounding brought the value out of range. */
60 feraiseexcept (FE_INVALID);
61#endif
62 }
63 }
64 else if (j0 < (int32_t) (8 * sizeof (long int)) - 1)
65 {
66 if (j0 >= 63)
67 result = ((long int) i0 << (j0 - 31)) | (i1 << (j0 - 63));
68 else
69 {
70 uint32_t j = i1 + (0x80000000 >> (j0 - 31));
71 unsigned long int ures = i0;
72
73 if (j < i1)
74 ++ures;
75
76 if (j0 == 31)
77 result = ures;
78 else
79 {
80 result = (ures << (j0 - 31)) | (j >> (63 - j0));
81#ifdef FE_INVALID
82 if (sizeof (long int) == 8
83 && sign == 1
84 && result == LONG_MIN)
85 /* Rounding brought the value out of range. */
86 feraiseexcept (FE_INVALID);
87#endif
88 }
89 }
90 }
91 else
92 {
93 /* The number is too large. Unless it rounds to LONG_MIN,
94 FE_INVALID must be raised and the return value is
95 unspecified. */
96#ifdef FE_INVALID
97 if (sizeof (long int) == 4
98 && x <= (long double) LONG_MIN - 0.5L)
99 {
100 /* If truncation produces LONG_MIN, the cast will not raise
101 the exception, but may raise "inexact". */
102 feraiseexcept (FE_INVALID);
103 return LONG_MIN;
104 }
105#endif
106 return (long int) x;
107 }
108
109 return sign * result;
110}
111
112libm_alias_ldouble (__lround, lround)
113