1 /* Round argument to nearest integral value according to current rounding
2 direction.
3 Copyright (C) 1997-2018 Free Software Foundation, Inc.
4 This file is part of the GNU C Library.
5 Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997 and
6 Jakub Jelinek <jj@ultra.linux.cz>, 1999.
7
8 The GNU C Library is free software; you can redistribute it and/or
9 modify it under the terms of the GNU Lesser General Public
10 License as published by the Free Software Foundation; either
11 version 2.1 of the License, or (at your option) any later version.
12
13 The GNU C Library is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 Lesser General Public License for more details.
17
18 You should have received a copy of the GNU Lesser General Public
19 License along with the GNU C Library; if not, see
20 <http://www.gnu.org/licenses/>. */
21
22 #include "quadmath-imp.h"
23
24 static const __float128 two112[2] =
25 {
26 5.19229685853482762853049632922009600E+33Q, /* 0x406F000000000000, 0 */
27 -5.19229685853482762853049632922009600E+33Q /* 0xC06F000000000000, 0 */
28 };
29
30 long int
lrintq(__float128 x)31 lrintq (__float128 x)
32 {
33 int32_t j0;
34 uint64_t i0,i1;
35 __float128 w;
36 __float128 t;
37 long int result;
38 int sx;
39
40 GET_FLT128_WORDS64 (i0, i1, x);
41 j0 = ((i0 >> 48) & 0x7fff) - 0x3fff;
42 sx = i0 >> 63;
43 i0 &= 0x0000ffffffffffffLL;
44 i0 |= 0x0001000000000000LL;
45
46 if (j0 < (int32_t) (8 * sizeof (long int)) - 1)
47 {
48 if (j0 < 48)
49 {
50 #if defined FE_INVALID || defined FE_INEXACT
51 /* X < LONG_MAX + 1 implied by J0 < 31. */
52 if (sizeof (long int) == 4
53 && x > (__float128) LONG_MAX)
54 {
55 /* In the event of overflow we must raise the "invalid"
56 exception, but not "inexact". */
57 t = nearbyintq (x);
58 feraiseexcept (t == LONG_MAX ? FE_INEXACT : FE_INVALID);
59 }
60 else
61 #endif
62 {
63 w = two112[sx] + x;
64 t = w - two112[sx];
65 }
66 GET_FLT128_WORDS64 (i0, i1, t);
67 j0 = ((i0 >> 48) & 0x7fff) - 0x3fff;
68 i0 &= 0x0000ffffffffffffLL;
69 i0 |= 0x0001000000000000LL;
70
71 result = (j0 < 0 ? 0 : i0 >> (48 - j0));
72 }
73 else if (j0 >= 112)
74 result = ((long int) i0 << (j0 - 48)) | (i1 << (j0 - 112));
75 else
76 {
77 #if defined FE_INVALID || defined FE_INEXACT
78 /* X < LONG_MAX + 1 implied by J0 < 63. */
79 if (sizeof (long int) == 8
80 && x > (__float128) LONG_MAX)
81 {
82 /* In the event of overflow we must raise the "invalid"
83 exception, but not "inexact". */
84 t = nearbyintq (x);
85 feraiseexcept (t == LONG_MAX ? FE_INEXACT : FE_INVALID);
86 }
87 else
88 #endif
89 {
90 w = two112[sx] + x;
91 t = w - two112[sx];
92 }
93 GET_FLT128_WORDS64 (i0, i1, t);
94 j0 = ((i0 >> 48) & 0x7fff) - 0x3fff;
95 i0 &= 0x0000ffffffffffffLL;
96 i0 |= 0x0001000000000000LL;
97
98 if (j0 == 48)
99 result = (long int) i0;
100 else
101 result = ((long int) i0 << (j0 - 48)) | (i1 >> (112 - j0));
102 }
103 }
104 else
105 {
106 /* The number is too large. Unless it rounds to LONG_MIN,
107 FE_INVALID must be raised and the return value is
108 unspecified. */
109 #if defined FE_INVALID || defined FE_INEXACT
110 if (x < (__float128) LONG_MIN
111 && x > (__float128) LONG_MIN - 1)
112 {
113 /* If truncation produces LONG_MIN, the cast will not raise
114 the exception, but may raise "inexact". */
115 t = nearbyintq (x);
116 feraiseexcept (t == LONG_MIN ? FE_INEXACT : FE_INVALID);
117 return LONG_MIN;
118 }
119 else if (FIX_FLT128_LONG_CONVERT_OVERFLOW && x != (__float128) LONG_MIN)
120 {
121 feraiseexcept (FE_INVALID);
122 return sx == 0 ? LONG_MAX : LONG_MIN;
123 }
124
125 #endif
126 return (long int) x;
127 }
128
129 return sx ? -result : result;
130 }
131