| 1 | /* mpn_mul_1 -- Multiply a limb vector with a single limb and |
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| 2 | store the product in a second limb vector. |
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| 3 | |
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| 4 | Copyright (C) 1991-2022 Free Software Foundation, Inc. |
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| 5 | |
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| 6 | This file is part of the GNU MP Library. |
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| 7 | |
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| 8 | The GNU MP Library is free software; you can redistribute it and/or modify |
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| 9 | it under the terms of the GNU Lesser General Public License as published by |
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| 10 | the Free Software Foundation; either version 2.1 of the License, or (at your |
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| 11 | option) any later version. |
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| 12 | |
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| 13 | The GNU MP Library is distributed in the hope that it will be useful, but |
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| 14 | WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY |
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| 15 | or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public |
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| 16 | License for more details. |
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| 17 | |
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| 18 | You should have received a copy of the GNU Lesser General Public License |
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| 19 | along with the GNU MP Library; see the file COPYING.LIB. If not, see |
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| 20 | <https://www.gnu.org/licenses/>. */ |
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| 21 | |
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| 22 | #include <gmp.h> |
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| 23 | #include "gmp-impl.h" |
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| 24 | #include "longlong.h" |
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| 25 | |
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| 26 | mp_limb_t |
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| 27 | mpn_mul_1 (register mp_ptr res_ptr, register mp_srcptr s1_ptr, |
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| 28 | mp_size_t s1_size, register mp_limb_t s2_limb) |
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| 29 | { |
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| 30 | register mp_limb_t cy_limb; |
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| 31 | register mp_size_t j; |
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| 32 | register mp_limb_t prod_high, prod_low; |
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| 33 | |
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| 34 | /* The loop counter and index J goes from -S1_SIZE to -1. This way |
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| 35 | the loop becomes faster. */ |
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| 36 | j = -s1_size; |
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| 37 | |
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| 38 | /* Offset the base pointers to compensate for the negative indices. */ |
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| 39 | s1_ptr -= j; |
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| 40 | res_ptr -= j; |
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| 41 | |
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| 42 | cy_limb = 0; |
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| 43 | do |
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| 44 | { |
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| 45 | umul_ppmm (prod_high, prod_low, s1_ptr[j], s2_limb); |
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| 46 | |
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| 47 | prod_low += cy_limb; |
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| 48 | cy_limb = (prod_low < cy_limb) + prod_high; |
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| 49 | |
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| 50 | res_ptr[j] = prod_low; |
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| 51 | } |
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| 52 | while (++j != 0); |
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| 53 | |
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| 54 | return cy_limb; |
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| 55 | } |
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| 56 | |
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