lh | 9ed821d | 2023-04-07 01:36:19 -0700 | [diff] [blame^] | 1 | /* mpn_mul_1 -- Multiply a limb vector with a single limb and |
| 2 | store the product in a second limb vector. |
| 3 | |
| 4 | Copyright (C) 1991-2015 Free Software Foundation, Inc. |
| 5 | |
| 6 | This file is part of the GNU MP Library. |
| 7 | |
| 8 | The GNU MP Library is free software; you can redistribute it and/or modify |
| 9 | it under the terms of the GNU Lesser General Public License as published by |
| 10 | the Free Software Foundation; either version 2.1 of the License, or (at your |
| 11 | option) any later version. |
| 12 | |
| 13 | The GNU MP Library is distributed in the hope that it will be useful, but |
| 14 | WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY |
| 15 | or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public |
| 16 | License for more details. |
| 17 | |
| 18 | You should have received a copy of the GNU Lesser General Public License |
| 19 | along with the GNU MP Library; see the file COPYING.LIB. If not, see |
| 20 | <http://www.gnu.org/licenses/>. */ |
| 21 | |
| 22 | #include <gmp.h> |
| 23 | #include "gmp-impl.h" |
| 24 | #include "longlong.h" |
| 25 | |
| 26 | mp_limb_t |
| 27 | mpn_mul_1 (res_ptr, s1_ptr, s1_size, s2_limb) |
| 28 | register mp_ptr res_ptr; |
| 29 | register mp_srcptr s1_ptr; |
| 30 | mp_size_t s1_size; |
| 31 | register mp_limb_t s2_limb; |
| 32 | { |
| 33 | register mp_limb_t cy_limb; |
| 34 | register mp_size_t j; |
| 35 | register mp_limb_t prod_high, prod_low; |
| 36 | |
| 37 | /* The loop counter and index J goes from -S1_SIZE to -1. This way |
| 38 | the loop becomes faster. */ |
| 39 | j = -s1_size; |
| 40 | |
| 41 | /* Offset the base pointers to compensate for the negative indices. */ |
| 42 | s1_ptr -= j; |
| 43 | res_ptr -= j; |
| 44 | |
| 45 | cy_limb = 0; |
| 46 | do |
| 47 | { |
| 48 | umul_ppmm (prod_high, prod_low, s1_ptr[j], s2_limb); |
| 49 | |
| 50 | prod_low += cy_limb; |
| 51 | cy_limb = (prod_low < cy_limb) + prod_high; |
| 52 | |
| 53 | res_ptr[j] = prod_low; |
| 54 | } |
| 55 | while (++j != 0); |
| 56 | |
| 57 | return cy_limb; |
| 58 | } |