2 * Copyright (c) 2016 Thomas Pornin <pornin@bolet.org>
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:
12 * The above copyright notice and this permission notice shall be
13 * included in all copies or substantial portions of the Software.
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
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21 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
29 br_i32_montymul(uint32_t *d, const uint32_t *x, const uint32_t *y,
30 const uint32_t *m, uint32_t m0i)
35 len = (m[0] + 31) >> 5;
38 for (u = 0; u < len; u ++) {
43 f = (d[1] + x[u + 1] * y[1]) * m0i;
46 for (v = 0; v < len; v ++) {
50 z = (uint64_t)d[v + 1] + MUL(xu, y[v + 1]) + r1;
53 z = (uint64_t)t + MUL(f, m[v + 1]) + r2;
60 d[len] = (uint32_t)zh;
65 * d[] may still be greater than m[] at that point; notably, the
66 * 'dh' word may be non-zero.
68 br_i32_sub(d, m, NEQ(dh, 0) | NOT(br_i32_sub(d, m, 0)));