File Coverage

src/int/i15_fmont.c
Criterion Covered Total %
statement 0 13 0.0
branch 0 6 0.0
condition n/a
subroutine n/a
pod n/a
total 0 19 0.0


line stmt bran cond sub pod time code
1             /*
2             * Copyright (c) 2017 Thomas Pornin
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 0           br_i15_from_monty(uint16_t *x, const uint16_t *m, uint16_t m0i)
30             {
31             size_t len, u, v;
32              
33 0           len = (m[0] + 15) >> 4;
34 0 0         for (u = 0; u < len; u ++) {
35             uint32_t f, cc;
36              
37 0           f = MUL15(x[1], m0i) & 0x7FFF;
38 0           cc = 0;
39 0 0         for (v = 0; v < len; v ++) {
40             uint32_t z;
41              
42 0           z = (uint32_t)x[v + 1] + MUL15(f, m[v + 1]) + cc;
43 0           cc = z >> 15;
44 0 0         if (v != 0) {
45 0           x[v] = z & 0x7FFF;
46             }
47             }
48 0           x[len] = cc;
49             }
50              
51             /*
52             * We may have to do an extra subtraction, but only if the
53             * value in x[] is indeed greater than or equal to that of m[],
54             * which is why we must do two calls (first call computes the
55             * carry, second call performs the subtraction only if the carry
56             * is 0).
57             */
58 0           br_i15_sub(x, m, NOT(br_i15_sub(x, m, 0)));
59 0           }