363f488d |
1 | /* -*-c-*- |
2 | * |
3 | * $Id: primorial.c,v 1.1 1999/12/22 15:51:02 mdw Exp $ |
4 | * |
5 | * Computes the product of the small primes |
6 | * |
7 | * (c) 1999 Straylight/Edgeware |
8 | */ |
9 | |
10 | /*----- Licensing notice --------------------------------------------------* |
11 | * |
12 | * This file is part of Catacomb. |
13 | * |
14 | * Catacomb is free software; you can redistribute it and/or modify |
15 | * it under the terms of the GNU Library General Public License as |
16 | * published by the Free Software Foundation; either version 2 of the |
17 | * License, or (at your option) any later version. |
18 | * |
19 | * Catacomb is distributed in the hope that it will be useful, |
20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
22 | * GNU Library General Public License for more details. |
23 | * |
24 | * You should have received a copy of the GNU Library General Public |
25 | * License along with Catacomb; if not, write to the Free |
26 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
27 | * MA 02111-1307, USA. |
28 | */ |
29 | |
30 | /*----- Revision history --------------------------------------------------* |
31 | * |
32 | * $Log: primorial.c,v $ |
33 | * Revision 1.1 1999/12/22 15:51:02 mdw |
34 | * Calculate product of small primes for DSA prime search. |
35 | * |
36 | */ |
37 | |
38 | /*----- Header files ------------------------------------------------------*/ |
39 | |
40 | #include "mp.h" |
41 | #include "primetab.h" |
42 | |
43 | /*----- Global variables --------------------------------------------------*/ |
44 | |
45 | mp *primorial = 0; |
46 | |
47 | /*----- Main code ---------------------------------------------------------*/ |
48 | |
49 | /* --- @primorial_setup@ --- * |
50 | * |
51 | * Arguments: --- |
52 | * |
53 | * Returns: --- |
54 | * |
55 | * Use: Computes the product of the small primes in the table |
56 | * @primetab@. |
57 | */ |
58 | |
59 | void primorial_setup(void) |
60 | { |
61 | mp *p; |
62 | mp q; |
63 | mpw qw; |
64 | int i; |
65 | |
66 | if (primorial) |
67 | return; |
68 | mp_build(&q, &qw, &qw + 1); |
69 | p = MP_ONE; |
70 | for (i = 0; i < NPRIME; i++) { |
71 | qw = primetab[i]; |
72 | p = mp_mul(p, p, &q); |
73 | } |
74 | mp_minimize(p); |
75 | primorial = p; |
76 | } |
77 | |
78 | /*----- That's all, folks -------------------------------------------------*/ |