Added generic API for date range validation (with callbacks).
[BearSSL] / int / i32_div32.c
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 uint32_t
29 br_divrem(uint32_t hi, uint32_t lo, uint32_t d, uint32_t *r)
30 {
31 /* TODO: optimize this */
32 uint32_t q;
33 uint32_t ch, cf;
34 int k;
35
36 q = 0;
37 ch = EQ(hi, d);
38 hi = MUX(ch, 0, hi);
39 for (k = 31; k > 0; k --) {
40 int j;
41 uint32_t w, ctl, hi2, lo2;
42
43 j = 32 - k;
44 w = (hi << j) | (lo >> k);
45 ctl = GE(w, d) | (hi >> k);
46 hi2 = (w - d) >> j;
47 lo2 = lo - (d << k);
48 hi = MUX(ctl, hi2, hi);
49 lo = MUX(ctl, lo2, lo);
50 q |= ctl << k;
51 }
52 cf = GE(lo, d) | hi;
53 q |= cf;
54 *r = MUX(cf, lo - d, lo);
55 return q;
56 }