projects / thirdparty / glibc.git / blame
| Commit | Line | Data |
|---|---|---|
| 63551311 | 1 | /* Round double to integer away from zero. |
| d4697bc9 | 2 | Copyright (C) 1997-2014 Free Software Foundation, Inc. |
| 63551311 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 | |
| 41bdb6e2 AJ |
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. | |
| 63551311 UD |
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 | |
| 41bdb6e2 | 14 | Lesser General Public License for more details. |
| 63551311 | 15 | |
| 41bdb6e2 | 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/>. */ | |
| 63551311 UD |
19 | |
| 20 | #include <math.h> | |
| 21 | ||
| 1ed0291c | 22 | #include <math_private.h> |
| 63551311 UD |
23 | |
| 24 | ||
| 25 | static const double huge = 1.0e300; | |
| 26 | ||
| 27 | ||
| 28 | double | |
| 29 | __round (double x) | |
| 30 | { | |
| 31 | int32_t i0, j0; | |
| 32 | u_int32_t i1; | |
| 33 | ||
| 34 | EXTRACT_WORDS (i0, i1, x); | |
| 35 | j0 = ((i0 >> 20) & 0x7ff) - 0x3ff; | |
| 36 | if (j0 < 20) | |
| 37 | { | |
| 38 | if (j0 < 0) | |
| 39 | { | |
| 80479147 | 40 | math_force_eval (huge + x); |
| d7826aa1 UD |
41 | |
| 42 | i0 &= 0x80000000; | |
| 43 | if (j0 == -1) | |
| 44 | i0 |= 0x3ff00000; | |
| 45 | i1 = 0; | |
| 63551311 UD |
46 | } |
| 47 | else | |
| 48 | { | |
| 49 | u_int32_t i = 0x000fffff >> j0; | |
| 50 | if (((i0 & i) | i1) == 0) | |
| 51 | /* X is integral. */ | |
| 52 | return x; | |
| 80479147 | 53 | math_force_eval (huge + x); |
| d7826aa1 UD |
54 | |
| 55 | /* Raise inexact if x != 0. */ | |
| 56 | i0 += 0x00080000 >> j0; | |
| 57 | i0 &= ~i; | |
| 58 | i1 = 0; | |
| 63551311 UD |
59 | } |
| 60 | } | |
| 61 | else if (j0 > 51) | |
| 62 | { | |
| 63 | if (j0 == 0x400) | |
| 64 | /* Inf or NaN. */ | |
| 65 | return x + x; | |
| 66 | else | |
| 67 | return x; | |
| 68 | } | |
| 69 | else | |
| 70 | { | |
| 71 | u_int32_t i = 0xffffffff >> (j0 - 20); | |
| 72 | if ((i1 & i) == 0) | |
| 73 | /* X is integral. */ | |
| 74 | return x; | |
| 75 | ||
| 80479147 | 76 | math_force_eval (huge + x); |
| d7826aa1 UD |
77 | |
| 78 | /* Raise inexact if x != 0. */ | |
| 79 | u_int32_t j = i1 + (1 << (51 - j0)); | |
| 80 | if (j < i1) | |
| 81 | i0 += 1; | |
| 82 | i1 = j; | |
| 63551311 UD |
83 | i1 &= ~i; |
| 84 | } | |
| 85 | ||
| 86 | INSERT_WORDS (x, i0, i1); | |
| 87 | return x; | |
| 88 | } | |
| 89 | weak_alias (__round, round) | |
| 90 | #ifdef NO_LONG_DOUBLE | |
| 91 | strong_alias (__round, __roundl) | |
| 92 | weak_alias (__round, roundl) | |
| 93 | #endif |