| lh | 9ed821d | 2023-04-07 01:36:19 -0700 | [diff] [blame] | 1 | /* Round argument to nearest integral value according to current rounding |
| 2 | direction. |
| 3 | Copyright (C) 1997, 2004, 2006 Free Software Foundation, Inc. |
| 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 |
| 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. |
| 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 |
| 15 | Lesser General Public License for more details. |
| 16 | |
| 17 | You should have received a copy of the GNU Lesser General Public |
| 18 | License along with the GNU C Library; if not, write to the Free |
| 19 | Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
| 20 | 02111-1307 USA. */ |
| 21 | |
| 22 | #include <features.h> |
| 23 | /* Prevent math.h from defining a colliding inline */ |
| 24 | #undef __USE_EXTERN_INLINES |
| 25 | #include <math.h> |
| 26 | #include "math_private.h" |
| 27 | |
| 28 | static const double two52[2] = |
| 29 | { |
| 30 | 4.50359962737049600000e+15, /* 0x43300000, 0x00000000 */ |
| 31 | -4.50359962737049600000e+15, /* 0xC3300000, 0x00000000 */ |
| 32 | }; |
| 33 | |
| 34 | long long int |
| 35 | llrint (double x) |
| 36 | { |
| 37 | int32_t j0; |
| 38 | u_int32_t i1, i0; |
| 39 | long long int result; |
| 40 | volatile double w; |
| 41 | double t; |
| 42 | int sx; |
| 43 | |
| 44 | EXTRACT_WORDS (i0, i1, x); |
| 45 | j0 = ((i0 >> 20) & 0x7ff) - 0x3ff; |
| 46 | sx = i0 >> 31; |
| 47 | i0 &= 0xfffff; |
| 48 | i0 |= 0x100000; |
| 49 | |
| 50 | if (j0 < 20) |
| 51 | { |
| 52 | w = two52[sx] + x; |
| 53 | t = w - two52[sx]; |
| 54 | EXTRACT_WORDS (i0, i1, t); |
| 55 | j0 = ((i0 >> 20) & 0x7ff) - 0x3ff; |
| 56 | i0 &= 0xfffff; |
| 57 | i0 |= 0x100000; |
| 58 | |
| 59 | result = (j0 < 0 ? 0 : i0 >> (20 - j0)); |
| 60 | } |
| 61 | else if (j0 < (int32_t) (8 * sizeof (long long int)) - 1) |
| 62 | { |
| 63 | if (j0 >= 52) |
| 64 | result = (((long long int) i0 << 32) | i1) << (j0 - 52); |
| 65 | else |
| 66 | { |
| 67 | w = two52[sx] + x; |
| 68 | t = w - two52[sx]; |
| 69 | EXTRACT_WORDS (i0, i1, t); |
| 70 | j0 = ((i0 >> 20) & 0x7ff) - 0x3ff; |
| 71 | i0 &= 0xfffff; |
| 72 | i0 |= 0x100000; |
| 73 | |
| 74 | if (j0 == 20) |
| 75 | result = (long long int) i0; |
| 76 | else |
| 77 | result = ((long long int) i0 << (j0 - 20)) | (i1 >> (52 - j0)); |
| 78 | } |
| 79 | } |
| 80 | else |
| 81 | { |
| 82 | /* The number is too large. It is left implementation defined |
| 83 | what happens. */ |
| 84 | return (long long int) x; |
| 85 | } |
| 86 | |
| 87 | return sx ? -result : result; |
| 88 | } |
| 89 | |
| 90 | libm_hidden_def(llrint) |