1 /* Round long double value to long long int.
2 Copyright (C) 1997-2018 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 <http://www.gnu.org/licenses/>. */
20
21 #include "quadmath-imp.h"
22
23 long long int
llroundq(__float128 x)24 llroundq (__float128 x)
25 {
26 int64_t j0;
27 uint64_t i1, i0;
28 long long int result;
29 int sign;
30
31 GET_FLT128_WORDS64 (i0, i1, x);
32 j0 = ((i0 >> 48) & 0x7fff) - 0x3fff;
33 sign = (i0 & 0x8000000000000000ULL) != 0 ? -1 : 1;
34 i0 &= 0x0000ffffffffffffLL;
35 i0 |= 0x0001000000000000LL;
36
37 if (j0 < 48)
38 {
39 if (j0 < 0)
40 return j0 < -1 ? 0 : sign;
41 else
42 {
43 i0 += 0x0000800000000000LL >> j0;
44 result = i0 >> (48 - j0);
45 }
46 }
47 else if (j0 < (int32_t) (8 * sizeof (long long int)) - 1)
48 {
49 if (j0 >= 112)
50 result = ((long long int) i0 << (j0 - 48)) | (i1 << (j0 - 112));
51 else
52 {
53 uint64_t j = i1 + (0x8000000000000000ULL >> (j0 - 48));
54 if (j < i1)
55 ++i0;
56
57 if (j0 == 48)
58 result = (long long int) i0;
59 else
60 {
61 result = ((long long int) i0 << (j0 - 48)) | (j >> (112 - j0));
62 #ifdef FE_INVALID
63 if (sign == 1 && result == LLONG_MIN)
64 /* Rounding brought the value out of range. */
65 feraiseexcept (FE_INVALID);
66 #endif
67 }
68 }
69 }
70 else
71 {
72 /* The number is too large. Unless it rounds to LLONG_MIN,
73 FE_INVALID must be raised and the return value is
74 unspecified. */
75 #ifdef FE_INVALID
76 if (FIX_FLT128_LLONG_CONVERT_OVERFLOW
77 && !(sign == -1 && x > (__float128) LLONG_MIN - 0.5Q))
78 {
79 feraiseexcept (FE_INVALID);
80 return sign == 1 ? LLONG_MAX : LLONG_MIN;
81 }
82 else if (!FIX_FLT128_LLONG_CONVERT_OVERFLOW
83 && x <= (__float128) LLONG_MIN - 0.5Q)
84 {
85 /* If truncation produces LLONG_MIN, the cast will not raise
86 the exception, but may raise "inexact". */
87 feraiseexcept (FE_INVALID);
88 return LLONG_MIN;
89 }
90 #endif
91 return (long long int) x;
92 }
93
94 return sign * result;
95 }
96