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
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
|
// file kernel/n/h/div_n2.h: O(n^2) division of natural integers
/*-----------------------------------------------------------------------+
| Copyright 2005-2006, Michel Quercia (michel.quercia@prepas.org) |
| |
| This file is part of Numerix. Numerix is free software; you can |
| redistribute it and/or modify it under the terms of the GNU Lesser |
| General Public License as published by the Free Software Foundation; |
| either version 2.1 of the License, or (at your option) any later |
| version. |
| |
| The Numerix Library is distributed in the hope that it will be |
| useful, but WITHOUT ANY WARRANTY; without even the implied warranty |
| of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public |
| License along with the GNU MP Library; see the file COPYING. If not, |
| write to the Free Software Foundation, Inc., 59 Temple Place - |
| Suite 330, Boston, MA 02111-1307, USA. |
+-----------------------------------------------------------------------+
| |
| Division quadratique |
| |
+-----------------------------------------------------------------------*/
/* ---------------------------------------- division deux chiffres par un
entre :
a,b,c,*d,*e = chiffres
contraintes : b < c, d,e non confondus et non confondus avec a,b,c
sortie :
*d <- floor((a + BASE*b)/c)
*e <- (a + BASE*b) mod c
remarque :
code inefficace, n'utiliser qu'en l'absence de ndoubles
*/
extern inline void xn(div_0)(chiffre a, chiffre b, chiffre c, chiffre *d, chiffre *e) {
long i;
int r;
/* division bit bit */
for (*d = 0, *e = b, i = 0; i < HW; i++) {
*d <<= 1;
r = (*e >= BASE_2);
*e = 2*(*e) + (a >= BASE_2);
if ((r) || (*e >= c)) {(*d)++; *e -= c;}
a <<= 1;
}
}
/* ---------------------------------------- Division par un long
entre :
a = naturel de longueur la >= 0
b = long > 0
c = naturel de longueur la, peut tre confondu avec a
sortie :
c <- floor(a/b)
retourne a mod b
*/
unsigned long xn(div_1)(chiffre *a, long la, unsigned long b, chiffre *c);
/*
entre :
a = naturel de longueur la >= 0
b = long > 0
sortie :
retourne a mod b
*/
unsigned long xn(mod_1)(chiffre *a, long la, unsigned long b);
/* ---------------------------------------- Division quadratique
entre :
a = naturel de longueur lc+lb
b = naturel de longueur lb
c = naturel de longueur lc
contraintes :
lb >= 2, lc > 0, le bit de poids fort de b est non nul,
a < BASE^lc*b
a,b,c non confondus
sortie :
a <- a mod b
c <- floor(a/b)
*/
void xn(div_n2)(chiffre *a, long lc, chiffre *b, long lb, chiffre *c);
|
