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1 | /* mpn_addmul_1 -- multiply the S1_SIZE long limb vector pointed to by S1_PTR |
2 | by S2_LIMB, add the S1_SIZE least significant limbs of the product to the | |
3 | limb vector pointed to by RES_PTR. Return the most significant limb of | |
4 | the product, adjusted for carry-out from the addition. | |
5 | ||
b168057a | 6 | Copyright (C) 1992-2015 Free Software Foundation, Inc. |
b6ab06ce UD |
7 | |
8 | This file is part of the GNU MP Library. | |
9 | ||
10 | The GNU MP Library is free software; you can redistribute it and/or modify | |
11 | it under the terms of the GNU Lesser General Public License as published by | |
12 | the Free Software Foundation; either version 2.1 of the License, or (at your | |
13 | option) any later version. | |
14 | ||
15 | The GNU MP Library is distributed in the hope that it will be useful, but | |
16 | WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY | |
17 | or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public | |
18 | License for more details. | |
19 | ||
20 | You should have received a copy of the GNU Lesser General Public License | |
59ba27a6 PE |
21 | along with the GNU MP Library; see the file COPYING.LIB. If not, see |
22 | <http://www.gnu.org/licenses/>. */ | |
b6ab06ce UD |
23 | |
24 | #include <gmp.h> | |
25 | #include "gmp-impl.h" | |
26 | #include "longlong.h" | |
27 | ||
28 | mp_limb_t | |
29 | mpn_addmul_1 (res_ptr, s1_ptr, s1_size, s2_limb) | |
30 | register mp_ptr res_ptr; | |
31 | register mp_srcptr s1_ptr; | |
32 | mp_size_t s1_size; | |
33 | register mp_limb_t s2_limb; | |
34 | { | |
35 | register mp_limb_t cy_limb; | |
36 | register mp_size_t j; | |
37 | register mp_limb_t prod_high, prod_low; | |
38 | register mp_limb_t x; | |
39 | ||
40 | /* The loop counter and index J goes from -SIZE to -1. This way | |
41 | the loop becomes faster. */ | |
42 | j = -s1_size; | |
43 | ||
44 | /* Offset the base pointers to compensate for the negative indices. */ | |
45 | res_ptr -= j; | |
46 | s1_ptr -= j; | |
47 | ||
48 | cy_limb = 0; | |
49 | do | |
50 | { | |
51 | umul_ppmm (prod_high, prod_low, s1_ptr[j], s2_limb); | |
52 | ||
53 | prod_low += cy_limb; | |
54 | cy_limb = (prod_low < cy_limb) + prod_high; | |
55 | ||
56 | x = res_ptr[j]; | |
57 | prod_low = x + prod_low; | |
58 | cy_limb += (prod_low < x); | |
59 | res_ptr[j] = prod_low; | |
60 | } | |
61 | while (++j != 0); | |
62 | ||
63 | return cy_limb; | |
64 | } |