xref: /freebsd/contrib/bearssl/src/int/i32_mulacc.c (revision f7c32ed617858bcd22f8d1b03199099d50125721)
1 /*
2  * Copyright (c) 2016 Thomas Pornin <pornin@bolet.org>
3  *
4  * Permission is hereby granted, free of charge, to any person obtaining
5  * a copy of this software and associated documentation files (the
6  * "Software"), to deal in the Software without restriction, including
7  * without limitation the rights to use, copy, modify, merge, publish,
8  * distribute, sublicense, and/or sell copies of the Software, and to
9  * permit persons to whom the Software is furnished to do so, subject to
10  * the following conditions:
11  *
12  * The above copyright notice and this permission notice shall be
13  * included in all copies or substantial portions of the Software.
14  *
15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
16  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
17  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
18  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
19  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
20  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
21  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
22  * SOFTWARE.
23  */
24 
25 #include "inner.h"
26 
27 /* see inner.h */
28 void
29 br_i32_mulacc(uint32_t *d, const uint32_t *a, const uint32_t *b)
30 {
31 	size_t alen, blen, u;
32 
33 	alen = (a[0] + 31) >> 5;
34 	blen = (b[0] + 31) >> 5;
35 	d[0] = a[0] + b[0];
36 	for (u = 0; u < blen; u ++) {
37 		uint32_t f;
38 		size_t v;
39 #if BR_64
40 		uint64_t cc;
41 #else
42 		uint32_t cc;
43 #endif
44 
45 		f = b[1 + u];
46 		cc = 0;
47 		for (v = 0; v < alen; v ++) {
48 			uint64_t z;
49 
50 			z = (uint64_t)d[1 + u + v] + MUL(f, a[1 + v]) + cc;
51 			cc = z >> 32;
52 			d[1 + u + v] = (uint32_t)z;
53 		}
54 		d[1 + u + alen] = (uint32_t)cc;
55 	}
56 }
57