projects / thirdparty / glibc.git / blame
| Commit | Line | Data |
|---|---|---|
| 84057895 | 1 | /* Round double to integer away from zero. |
| f7a9f785 | 2 | Copyright (C) 1997-2016 Free Software Foundation, Inc. |
| 84057895 UD |
3 | This file is part of the GNU C Library. |
| 4 | Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997. | |
| 5 | ||
| 6 | The GNU C Library is free software; you can redistribute it and/or | |
| 7 | modify it under the terms of the GNU Lesser General Public | |
| 8 | License as published by the Free Software Foundation; either | |
| 9 | version 2.1 of the License, or (at your option) any later version. | |
| 10 | ||
| 11 | The GNU C Library is distributed in the hope that it will be useful, | |
| 12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| 14 | Lesser General Public License for more details. | |
| 15 | ||
| 16 | You should have received a copy of the GNU Lesser General Public | |
| 59ba27a6 PE |
17 | License along with the GNU C Library; if not, see |
| 18 | <http://www.gnu.org/licenses/>. */ | |
| 84057895 UD |
19 | |
| 20 | #include <math.h> | |
| 21 | ||
| 1ed0291c | 22 | #include <math_private.h> |
| e054f494 | 23 | #include <stdint.h> |
| 84057895 UD |
24 | |
| 25 | static const double huge = 1.0e300; | |
| 26 | ||
| 27 | ||
| 28 | double | |
| 29 | __round (double x) | |
| 30 | { | |
| 31 | int64_t i0, j0; | |
| 32 | ||
| 33 | EXTRACT_WORDS64 (i0, x); | |
| 34 | j0 = ((i0 >> 52) & 0x7ff) - 0x3ff; | |
| a1ffb40e | 35 | if (__glibc_likely (j0 < 52)) |
| 84057895 UD |
36 | { |
| 37 | if (j0 < 0) | |
| 38 | { | |
| d7826aa1 UD |
39 | math_force_eval (huge + x); |
| 40 | ||
| 41 | i0 &= UINT64_C(0x8000000000000000); | |
| 42 | if (j0 == -1) | |
| 43 | i0 |= UINT64_C(0x3ff0000000000000); | |
| 84057895 UD |
44 | } |
| 45 | else | |
| 46 | { | |
| 47 | uint64_t i = UINT64_C(0x000fffffffffffff) >> j0; | |
| 48 | if ((i0 & i) == 0) | |
| 49 | /* X is integral. */ | |
| 50 | return x; | |
| d7826aa1 UD |
51 | math_force_eval (huge + x); |
| 52 | ||
| 53 | /* Raise inexact if x != 0. */ | |
| 54 | i0 += UINT64_C(0x0008000000000000) >> j0; | |
| 55 | i0 &= ~i; | |
| 84057895 UD |
56 | } |
| 57 | } | |
| 58 | else | |
| 59 | { | |
| 60 | if (j0 == 0x400) | |
| 61 | /* Inf or NaN. */ | |
| 62 | return x + x; | |
| 63 | else | |
| 64 | return x; | |
| 65 | } | |
| 66 | ||
| 67 | INSERT_WORDS64 (x, i0); | |
| 68 | return x; | |
| 69 | } | |
| 70 | weak_alias (__round, round) | |
| 71 | #ifdef NO_LONG_DOUBLE | |
| 72 | strong_alias (__round, __roundl) | |
| 73 | weak_alias (__round, roundl) | |
| 74 | #endif |