| 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 -------------------------------------------------*/ |