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Commit | Line | Data |
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c131718c UD |
1 | /* Round argument to nearest integral value according to current rounding |
2 | direction. | |
04277e02 | 3 | Copyright (C) 1997-2019 Free Software Foundation, Inc. |
c131718c UD |
4 | This file is part of the GNU C Library. |
5 | Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997. | |
6 | ||
7 | The GNU C Library is free software; you can redistribute it and/or | |
41bdb6e2 AJ |
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. | |
c131718c UD |
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 | |
41bdb6e2 | 15 | Lesser General Public License for more details. |
c131718c | 16 | |
41bdb6e2 | 17 | You should have received a copy of the GNU Lesser General Public |
59ba27a6 | 18 | License along with the GNU C Library; if not, see |
5a82c748 | 19 | <https://www.gnu.org/licenses/>. */ |
c131718c | 20 | |
d0d286d3 JM |
21 | #include <fenv.h> |
22 | #include <limits.h> | |
c131718c UD |
23 | #include <math.h> |
24 | ||
aaee3cd8 | 25 | #include <math-narrow-eval.h> |
1ed0291c | 26 | #include <math_private.h> |
1e2bffd0 | 27 | #include <libm-alias-double.h> |
06d97e5e | 28 | #include <fix-fp-int-convert-overflow.h> |
c131718c | 29 | |
dfd2257a | 30 | static const double two52[2] = |
c131718c UD |
31 | { |
32 | 4.50359962737049600000e+15, /* 0x43300000, 0x00000000 */ | |
33 | -4.50359962737049600000e+15, /* 0xC3300000, 0x00000000 */ | |
34 | }; | |
35 | ||
36 | ||
37 | long int | |
dfd2257a | 38 | __lrint (double x) |
c131718c | 39 | { |
dfd2257a | 40 | int32_t j0; |
24ab7723 | 41 | uint32_t i0, i1; |
54142c44 | 42 | double w; |
dfd2257a | 43 | double t; |
c131718c | 44 | long int result; |
dfd2257a | 45 | int sx; |
c131718c UD |
46 | |
47 | EXTRACT_WORDS (i0, i1, x); | |
c131718c | 48 | j0 = ((i0 >> 20) & 0x7ff) - 0x3ff; |
dfd2257a UD |
49 | sx = i0 >> 31; |
50 | i0 &= 0xfffff; | |
51 | i0 |= 0x100000; | |
c131718c UD |
52 | |
53 | if (j0 < 20) | |
54 | { | |
54142c44 | 55 | w = math_narrow_eval (two52[sx] + x); |
6624dbc0 UD |
56 | t = w - two52[sx]; |
57 | EXTRACT_WORDS (i0, i1, t); | |
58 | j0 = ((i0 >> 20) & 0x7ff) - 0x3ff; | |
59 | i0 &= 0xfffff; | |
60 | i0 |= 0x100000; | |
dfd2257a | 61 | |
6624dbc0 | 62 | result = (j0 < 0 ? 0 : i0 >> (20 - j0)); |
c131718c | 63 | } |
cc3fa755 | 64 | else if (j0 < (int32_t) (8 * sizeof (long int)) - 1) |
c131718c | 65 | { |
dfd2257a | 66 | if (j0 >= 52) |
0e069029 | 67 | result = ((long int) i0 << (j0 - 20)) | ((long int) i1 << (j0 - 52)); |
c131718c UD |
68 | else |
69 | { | |
d0d286d3 JM |
70 | #if defined FE_INVALID || defined FE_INEXACT |
71 | /* X < LONG_MAX + 1 implied by J0 < 31. */ | |
72 | if (sizeof (long int) == 4 | |
73 | && x > (double) LONG_MAX) | |
74 | { | |
75 | /* In the event of overflow we must raise the "invalid" | |
76 | exception, but not "inexact". */ | |
77 | t = __nearbyint (x); | |
78 | feraiseexcept (t == LONG_MAX ? FE_INEXACT : FE_INVALID); | |
79 | } | |
80 | else | |
81 | #endif | |
82 | { | |
83 | w = math_narrow_eval (two52[sx] + x); | |
84 | t = w - two52[sx]; | |
85 | } | |
dfd2257a | 86 | EXTRACT_WORDS (i0, i1, t); |
dfd2257a | 87 | j0 = ((i0 >> 20) & 0x7ff) - 0x3ff; |
6973fc01 UD |
88 | i0 &= 0xfffff; |
89 | i0 |= 0x100000; | |
dfd2257a | 90 | |
3eb61415 UD |
91 | if (j0 == 20) |
92 | result = (long int) i0; | |
93 | else | |
94 | result = ((long int) i0 << (j0 - 20)) | (i1 >> (52 - j0)); | |
c131718c UD |
95 | } |
96 | } | |
dfd2257a | 97 | else |
c131718c | 98 | { |
d0d286d3 JM |
99 | /* The number is too large. Unless it rounds to LONG_MIN, |
100 | FE_INVALID must be raised and the return value is | |
101 | unspecified. */ | |
102 | #if defined FE_INVALID || defined FE_INEXACT | |
103 | if (sizeof (long int) == 4 | |
104 | && x < (double) LONG_MIN | |
105 | && x > (double) LONG_MIN - 1.0) | |
106 | { | |
107 | /* If truncation produces LONG_MIN, the cast will not raise | |
108 | the exception, but may raise "inexact". */ | |
109 | t = __nearbyint (x); | |
110 | feraiseexcept (t == LONG_MIN ? FE_INEXACT : FE_INVALID); | |
111 | return LONG_MIN; | |
112 | } | |
06d97e5e JM |
113 | else if (FIX_DBL_LONG_CONVERT_OVERFLOW && x != (double) LONG_MIN) |
114 | { | |
115 | feraiseexcept (FE_INVALID); | |
116 | return sx == 0 ? LONG_MAX : LONG_MIN; | |
117 | } | |
d0d286d3 | 118 | #endif |
dfd2257a | 119 | return (long int) x; |
c131718c | 120 | } |
c131718c | 121 | |
dfd2257a | 122 | return sx ? -result : result; |
c131718c | 123 | } |
c131718c | 124 | |
1e2bffd0 | 125 | libm_alias_double (__lrint, lrint) |