| lh | 9ed821d | 2023-04-07 01:36:19 -0700 | [diff] [blame^] | 1 | /* Round double value to long long int. |
| 2 | Copyright (C) 1997 Free Software Foundation, Inc. |
| 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 |
| 17 | License along with the GNU C Library; if not, write to the Free |
| 18 | Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
| 19 | 02111-1307 USA. */ |
| 20 | |
| 21 | #include <math.h> |
| 22 | #include "math_private.h" |
| 23 | |
| 24 | long long int |
| 25 | llround (double x) |
| 26 | { |
| 27 | int32_t j0; |
| 28 | u_int32_t i1, i0; |
| 29 | long long int result; |
| 30 | int sign; |
| 31 | |
| 32 | EXTRACT_WORDS (i0, i1, x); |
| 33 | j0 = ((i0 >> 20) & 0x7ff) - 0x3ff; |
| 34 | sign = (i0 & 0x80000000) != 0 ? -1 : 1; |
| 35 | i0 &= 0xfffff; |
| 36 | i0 |= 0x100000; |
| 37 | |
| 38 | if (j0 < 20) |
| 39 | { |
| 40 | if (j0 < 0) |
| 41 | return j0 < -1 ? 0 : sign; |
| 42 | else |
| 43 | { |
| 44 | i0 += 0x80000 >> j0; |
| 45 | |
| 46 | result = i0 >> (20 - j0); |
| 47 | } |
| 48 | } |
| 49 | else if (j0 < (int32_t) (8 * sizeof (long long int)) - 1) |
| 50 | { |
| 51 | if (j0 >= 52) |
| 52 | result = (((long long int) i0 << 32) | i1) << (j0 - 52); |
| 53 | else |
| 54 | { |
| 55 | u_int32_t j = i1 + (0x80000000 >> (j0 - 20)); |
| 56 | if (j < i1) |
| 57 | ++i0; |
| 58 | |
| 59 | if (j0 == 20) |
| 60 | result = (long long int) i0; |
| 61 | else |
| 62 | result = ((long long int) i0 << (j0 - 20)) | (j >> (52 - j0)); |
| 63 | } |
| 64 | } |
| 65 | else |
| 66 | { |
| 67 | /* The number is too large. It is left implementation defined |
| 68 | what happens. */ |
| 69 | return (long long int) x; |
| 70 | } |
| 71 | |
| 72 | return sign * result; |
| 73 | } |
| 74 | libm_hidden_def(llround) |