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6b628d36 | 1 | /* mpn_mul_1 -- Multiply a limb vector with a single limb and |
28f540f4 RM |
2 | store the product in a second limb vector. |
3 | ||
581c785b | 4 | Copyright (C) 1991-2022 Free Software Foundation, Inc. |
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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 | |
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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 | |
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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 | |
6d84f89a | 15 | or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public |
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16 | License for more details. |
17 | ||
6d84f89a | 18 | You should have received a copy of the GNU Lesser General Public License |
59ba27a6 | 19 | along with the GNU MP Library; see the file COPYING.LIB. If not, see |
5a82c748 | 20 | <https://www.gnu.org/licenses/>. */ |
28f540f4 | 21 | |
9d13fb24 | 22 | #include <gmp.h> |
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23 | #include "gmp-impl.h" |
24 | #include "longlong.h" | |
25 | ||
b928942e | 26 | mp_limb_t |
f63f2bfd JM |
27 | mpn_mul_1 (register mp_ptr res_ptr, register mp_srcptr s1_ptr, |
28 | mp_size_t s1_size, register mp_limb_t s2_limb) | |
28f540f4 | 29 | { |
b928942e | 30 | register mp_limb_t cy_limb; |
28f540f4 | 31 | register mp_size_t j; |
b928942e | 32 | register mp_limb_t prod_high, prod_low; |
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33 | |
34 | /* The loop counter and index J goes from -S1_SIZE to -1. This way | |
35 | the loop becomes faster. */ | |
36 | j = -s1_size; | |
37 | ||
38 | /* Offset the base pointers to compensate for the negative indices. */ | |
39 | s1_ptr -= j; | |
40 | res_ptr -= j; | |
41 | ||
42 | cy_limb = 0; | |
43 | do | |
44 | { | |
45 | umul_ppmm (prod_high, prod_low, s1_ptr[j], s2_limb); | |
46 | ||
47 | prod_low += cy_limb; | |
48 | cy_limb = (prod_low < cy_limb) + prod_high; | |
49 | ||
50 | res_ptr[j] = prod_low; | |
51 | } | |
52 | while (++j != 0); | |
53 | ||
54 | return cy_limb; | |
55 | } |