1/* Round long double value to long int.
2 Copyright (C) 1997-2021 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4 Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997 and
5 Jakub Jelinek <jj@ultra.linux.cz>, 1999.
6
7 The GNU C Library is free software; you can redistribute it and/or
8 modify it under the terms of the GNU Lesser General Public
9 License as published by the Free Software Foundation; either
10 version 2.1 of the License, or (at your option) any later version.
11
12 The GNU C Library is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 Lesser General Public License for more details.
16
17 You should have received a copy of the GNU Lesser General Public
18 License along with the GNU C Library; if not, see
19 <https://www.gnu.org/licenses/>. */
20
21#include <fenv.h>
22#include <limits.h>
23#include <math.h>
24
25#include <math_private.h>
26#include <libm-alias-ldouble.h>
27#include <fix-fp-int-convert-overflow.h>
28
29long int
30__lroundl (_Float128 x)
31{
32 int64_t j0;
33 uint64_t i1, i0;
34 long int result;
35 int sign;
36
37 GET_LDOUBLE_WORDS64 (i0, i1, x);
38 j0 = ((i0 >> 48) & 0x7fff) - 0x3fff;
39 sign = (i0 & 0x8000000000000000ULL) != 0 ? -1 : 1;
40 i0 &= 0x0000ffffffffffffLL;
41 i0 |= 0x0001000000000000LL;
42
43 if (j0 < (int32_t) (8 * sizeof (long int)) - 1)
44 {
45 if (j0 < 48)
46 {
47 if (j0 < 0)
48 return j0 < -1 ? 0 : sign;
49 else
50 {
51 i0 += 0x0000800000000000LL >> j0;
52 result = i0 >> (48 - j0);
53#ifdef FE_INVALID
54 if (sizeof (long int) == 4
55 && sign == 1
56 && result == LONG_MIN)
57 /* Rounding brought the value out of range. */
58 feraiseexcept (FE_INVALID);
59#endif
60 }
61 }
62 else if (j0 >= 112)
63 result = ((long int) i0 << (j0 - 48)) | (i1 << (j0 - 112));
64 else
65 {
66 uint64_t j = i1 + (0x8000000000000000ULL >> (j0 - 48));
67 if (j < i1)
68 ++i0;
69
70 if (j0 == 48)
71 result = (long int) i0;
72 else
73 {
74 result = ((long int) i0 << (j0 - 48)) | (j >> (112 - j0));
75#ifdef FE_INVALID
76 if (sizeof (long int) == 8
77 && sign == 1
78 && result == LONG_MIN)
79 /* Rounding brought the value out of range. */
80 feraiseexcept (FE_INVALID);
81#endif
82 }
83 }
84 }
85 else
86 {
87 /* The number is too large. Unless it rounds to LONG_MIN,
88 FE_INVALID must be raised and the return value is
89 unspecified. */
90#ifdef FE_INVALID
91 if (FIX_LDBL_LONG_CONVERT_OVERFLOW
92 && !(sign == -1 && x > (_Float128) LONG_MIN - L(0.5)))
93 {
94 feraiseexcept (FE_INVALID);
95 return sign == 1 ? LONG_MAX : LONG_MIN;
96 }
97 else if (!FIX_LDBL_LONG_CONVERT_OVERFLOW
98 && x <= (_Float128) LONG_MIN - L(0.5))
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 /* The number is too large. It is left implementation defined
107 what happens. */
108 return (long int) x;
109 }
110
111 return sign * result;
112}
113
114libm_alias_ldouble (__lround, lround)
115