1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
|
/* ISC license. */
#include <errno.h>
#include <skalibs/uint32.h>
#include <skalibs/biguint.h>
/*
q = a/b, a = a mod b. Assumes b != 0 and qn >= alen - blen + 1.
*/
void bu_div_internal (uint32 *a, unsigned int an, uint32 const *b, unsigned int bn, uint32 *q, unsigned int qn)
{
unsigned int alen = bu_len(a, an) ;
unsigned int blen = bu_len(b, bn) ;
bu_zero(q, qn) ;
if (alen < blen) return ;
{
uint32 bb[alen + 1] ;
unsigned int i = 1 + ((alen - blen) << 5) ;
bu_zero(bb, alen - blen) ;
bu_copy_internal(bb + alen - blen, b, blen) ;
bb[alen] = 0 ;
while (bu_cmp(a, alen, bb, alen+1) >= 0)
{
bu_slb(bb + alen - blen, blen + 1) ;
i++ ;
}
while (i && (bu_cmp(a, alen, bb, alen+1) < 0))
{
bu_srb(bb, alen + 1) ;
i-- ;
}
while (i--)
{
bu_slb(q, alen - blen + 1) ;
if (bu_cmp(a, alen, bb, alen) >= 0)
{
bu_sub(a, alen, a, alen, bb, alen) ;
q[0] |= 1 ;
}
bu_srb(bb, alen) ;
}
}
}
|
