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  }