projects / thirdparty / glibc.git / blame
| Commit | Line | Data |
|---|---|---|
| b9b49b44 | 1 | /* Round double value to long long int. |
| 688903eb | 2 | Copyright (C) 1997-2018 Free Software Foundation, Inc. |
| 0413b54c UD |
3 | This file is part of the GNU C Library. |
| 4 | ||
| 5 | The GNU C Library is free software; you can redistribute it and/or | |
| 41bdb6e2 AJ |
6 | modify it under the terms of the GNU Lesser General Public |
| 7 | License as published by the Free Software Foundation; either | |
| 8 | version 2.1 of the License, or (at your option) any later version. | |
| 0413b54c UD |
9 | |
| 10 | The GNU C Library is distributed in the hope that it will be useful, | |
| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| 41bdb6e2 | 13 | Lesser General Public License for more details. |
| 0413b54c | 14 | |
| 41bdb6e2 | 15 | You should have received a copy of the GNU Lesser General Public |
| 59ba27a6 PE |
16 | License along with the GNU C Library; if not, see |
| 17 | <http://www.gnu.org/licenses/>. */ | |
| 0413b54c | 18 | |
| d7025bad | 19 | #include <limits.h> |
| 0413b54c | 20 | #include <math.h> |
| fce14d4e | 21 | #include <math_ldbl_opt.h> |
| d7025bad JM |
22 | #include <math_private.h> |
| 23 | #include <stdint.h> | |
| d17542d2 | 24 | #include <libm-alias-double.h> |
| 0413b54c | 25 | |
| da13146d AM |
26 | /* Round to the nearest integer, with values exactly on a 0.5 boundary |
| 27 | rounded away from zero, regardless of the current rounding mode. | |
| 28 | If (long long)x, when x is out of range of a long long, clips at | |
| 29 | LLONG_MAX or LLONG_MIN, then this implementation also clips. */ | |
| 0413b54c UD |
30 | |
| 31 | long long int | |
| b9b49b44 | 32 | __llround (double x) |
| 0413b54c | 33 | { |
| d7025bad JM |
34 | long long xr; |
| 35 | if (HAVE_PPC_FCTIDZ) | |
| 36 | xr = (long long) x; | |
| 37 | else | |
| 38 | { | |
| 39 | /* Avoid incorrect exceptions from libgcc conversions (as of GCC | |
| 40 | 5): <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59412>. */ | |
| 41 | if (fabs (x) < 0x1p31) | |
| 42 | xr = (long long int) (long int) x; | |
| 43 | else | |
| 44 | { | |
| 45 | uint64_t i0; | |
| 46 | EXTRACT_WORDS64 (i0, x); | |
| 47 | int exponent = ((i0 >> 52) & 0x7ff) - 0x3ff; | |
| 48 | if (exponent < 63) | |
| 49 | { | |
| 50 | unsigned long long int mant | |
| 51 | = (i0 & ((1ULL << 52) - 1)) | (1ULL << 52); | |
| 52 | if (exponent < 52) | |
| 53 | /* llround is not required to raise "inexact". */ | |
| 54 | mant >>= 52 - exponent; | |
| 55 | else | |
| 56 | mant <<= exponent - 52; | |
| 57 | xr = (long long int) ((i0 & (1ULL << 63)) != 0 ? -mant : mant); | |
| 58 | } | |
| 59 | else if (x == (double) LLONG_MIN) | |
| 60 | xr = LLONG_MIN; | |
| 61 | else | |
| 62 | xr = (long long int) (long int) x << 32; | |
| 63 | } | |
| 64 | } | |
| 65 | /* Avoid spurious "inexact" converting LLONG_MAX to double, and from | |
| 66 | subtraction when the result is out of range, by returning early | |
| 67 | for arguments large enough that no rounding is needed. */ | |
| 68 | if (!(fabs (x) < 0x1p52)) | |
| 69 | return xr; | |
| da13146d AM |
70 | double xrf = (double) xr; |
| 71 | ||
| 0413b54c | 72 | if (x >= 0.0) |
| da13146d AM |
73 | { |
| 74 | if (x - xrf >= 0.5) | |
| 75 | xr += (long long) ((unsigned long long) xr + 1) > 0; | |
| 76 | } | |
| 0413b54c | 77 | else |
| da13146d AM |
78 | { |
| 79 | if (xrf - x >= 0.5) | |
| 80 | xr -= (long long) ((unsigned long long) xr - 1) < 0; | |
| 81 | } | |
| 82 | return xr; | |
| 0413b54c | 83 | } |
| d17542d2 | 84 | libm_alias_double (__llround, llround) |