| Austin Schuh | bb1338c | 2024-06-15 19:31:16 -0700 | [diff] [blame] | 1 | /* mpz_sqrtrem(root,rem,x) -- Set ROOT to floor(sqrt(X)) and REM |
| 2 | to the remainder, i.e. X - ROOT**2. |
| 3 | |
| 4 | Copyright 1991, 1993, 1994, 1996, 2000, 2001, 2005, 2011, 2012, 2015 Free |
| 5 | Software Foundation, Inc. |
| 6 | |
| 7 | This file is part of the GNU MP Library. |
| 8 | |
| 9 | The GNU MP Library is free software; you can redistribute it and/or modify |
| 10 | it under the terms of either: |
| 11 | |
| 12 | * the GNU Lesser General Public License as published by the Free |
| 13 | Software Foundation; either version 3 of the License, or (at your |
| 14 | option) any later version. |
| 15 | |
| 16 | or |
| 17 | |
| 18 | * the GNU General Public License as published by the Free Software |
| 19 | Foundation; either version 2 of the License, or (at your option) any |
| 20 | later version. |
| 21 | |
| 22 | or both in parallel, as here. |
| 23 | |
| 24 | The GNU MP Library is distributed in the hope that it will be useful, but |
| 25 | WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY |
| 26 | or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 27 | for more details. |
| 28 | |
| 29 | You should have received copies of the GNU General Public License and the |
| 30 | GNU Lesser General Public License along with the GNU MP Library. If not, |
| 31 | see https://www.gnu.org/licenses/. */ |
| 32 | |
| 33 | #include "gmp-impl.h" |
| 34 | |
| 35 | void |
| 36 | mpz_sqrtrem (mpz_ptr root, mpz_ptr rem, mpz_srcptr op) |
| 37 | { |
| 38 | mp_size_t op_size, root_size, rem_size; |
| 39 | mp_ptr root_ptr, op_ptr, rem_ptr; |
| 40 | |
| 41 | op_size = SIZ (op); |
| 42 | if (UNLIKELY (op_size <= 0)) |
| 43 | { |
| 44 | if (UNLIKELY (op_size < 0)) |
| 45 | SQRT_OF_NEGATIVE; |
| 46 | SIZ(root) = 0; |
| 47 | SIZ(rem) = 0; |
| 48 | return; |
| 49 | } |
| 50 | |
| 51 | /* No-op if rem == op */ |
| 52 | rem_ptr = MPZ_NEWALLOC (rem, op_size); |
| 53 | |
| 54 | /* The size of the root is accurate after this simple calculation. */ |
| 55 | root_size = (op_size + 1) / 2; |
| 56 | SIZ (root) = root_size; |
| 57 | |
| 58 | op_ptr = PTR (op); |
| 59 | |
| 60 | if (root == op) |
| 61 | { |
| 62 | /* Allocate temp space for the root, which we then copy to the |
| 63 | shared OP/ROOT variable. */ |
| 64 | TMP_DECL; |
| 65 | TMP_MARK; |
| 66 | |
| 67 | root_ptr = TMP_ALLOC_LIMBS (root_size); |
| 68 | rem_size = mpn_sqrtrem (root_ptr, rem_ptr, op_ptr, op_size); |
| 69 | |
| 70 | if (rem != root) /* Don't overwrite remainder */ |
| 71 | MPN_COPY (op_ptr, root_ptr, root_size); |
| 72 | |
| 73 | TMP_FREE; |
| 74 | } |
| 75 | else |
| 76 | { |
| 77 | root_ptr = MPZ_NEWALLOC (root, root_size); |
| 78 | |
| 79 | rem_size = mpn_sqrtrem (root_ptr, rem_ptr, op_ptr, op_size); |
| 80 | } |
| 81 | |
| 82 | /* Write remainder size last, to make this function give only the square root |
| 83 | remainder, when passed ROOT == REM. */ |
| 84 | SIZ (rem) = rem_size; |
| 85 | } |