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#include <fix-fp-int-convert-overflow.h>
26
27long int
28__lroundl (_Float128 x)
29{
30 int64_t j0;
31 uint64_t i1, i0;
32 long int result;
33 int sign;
34
35 GET_LDOUBLE_WORDS64 (i0, i1, x);
36 j0 = ((i0 >> 48) & 0x7fff) - 0x3fff;
37 sign = (i0 & 0x8000000000000000ULL) != 0 ? -1 : 1;
38 i0 &= 0x0000ffffffffffffLL;
39 i0 |= 0x0001000000000000LL;
40
41 if (j0 < (int32_t) (8 * sizeof (long int)) - 1)
42 {
43 if (j0 < 48)
44 {
45 if (j0 < 0)
46 return j0 < -1 ? 0 : sign;
47 else
48 {
49 i0 += 0x0000800000000000LL >> j0;
50 result = i0 >> (48 - j0);
51#ifdef FE_INVALID
52 if (sizeof (long int) == 4
53 && sign == 1
54 && result == LONG_MIN)
55 /* Rounding brought the value out of range. */
56 feraiseexcept (FE_INVALID);
57#endif
58 }
59 }
60 else if (j0 >= 112)
61 result = ((long int) i0 << (j0 - 48)) | (i1 << (j0 - 112));
62 else
63 {
64 uint64_t j = i1 + (0x8000000000000000ULL >> (j0 - 48));
65 if (j < i1)
66 ++i0;
67
68 if (j0 == 48)
69 result = (long int) i0;
70 else
71 {
72 result = ((long int) i0 << (j0 - 48)) | (j >> (112 - j0));
73#ifdef FE_INVALID
74 if (sizeof (long int) == 8
75 && sign == 1
76 && result == LONG_MIN)
77 /* Rounding brought the value out of range. */
78 feraiseexcept (FE_INVALID);
79#endif
80 }
81 }
82 }
83 else
84 {
85 /* The number is too large. Unless it rounds to LONG_MIN,
86 FE_INVALID must be raised and the return value is
87 unspecified. */
88#ifdef FE_INVALID
89 if (FIX_LDBL_LONG_CONVERT_OVERFLOW
90 && !(sign == -1 && x > (_Float128) LONG_MIN - L(0.5)))
91 {
92 feraiseexcept (FE_INVALID);
93 return sign == 1 ? LONG_MAX : LONG_MIN;
94 }
95 else if (!FIX_LDBL_LONG_CONVERT_OVERFLOW
96 && x <= (_Float128) LONG_MIN - L(0.5))
97 {
98 /* If truncation produces LONG_MIN, the cast will not raise
99 the exception, but may raise "inexact". */
100 feraiseexcept (FE_INVALID);
101 return LONG_MIN;
102 }
103#endif
104 /* The number is too large. It is left implementation defined
105 what happens. */
106 return (long int) x;
107 }
108
109 return sign * result;
110}
111
112libm_alias_ldouble (__lround, lround)
113