/* -*-c-*-
*
- * $Id: pgen-gcd.c,v 1.1 2000/06/17 11:51:53 mdw Exp $
+ * $Id: pgen-gcd.c,v 1.3 2004/04/08 01:36:15 mdw Exp $
*
* Prime search stepper ensuring a low GCD for %$(p - 1)/2$%
*
* MA 02111-1307, USA.
*/
-/*----- Revision history --------------------------------------------------*
- *
- * $Log: pgen-gcd.c,v $
- * Revision 1.1 2000/06/17 11:51:53 mdw
- * Filter which imposes additional restrictions on GCD of %$(p - 1)/2$%
- * with a given integer.
- *
- */
-
/*----- Header files ------------------------------------------------------*/
#include "mp.h"
/* --- Set everything up --- *
*
- * Call things off if @q@ and @jq@ have common factors.
+ * Call things off if @p@ and @jp@ have common factors, or if @q@, @r@
+ * and @jq@ have common factors greater than @max@.
*/
case PGEN_BEGIN: {
mp *p = ev->m;
+ mp_gcd(&g->g, 0, 0, p, g->jp.m);
+ if (MP_CMP(g->g, >, MP_ONE))
+ return (PGEN_ABORT);
g->q = mp_lsr(MP_NEW, p, 1);
g->jq = mp_lsr(MP_NEW, g->jp.m, 1);
mp_gcd(&g->g, 0, 0, g->q, g->jq);
- if (MP_CMP(g->g, >, MP_ONE))
+ mp_gcd(&g->g, 0, 0, g->g, g->r);
+ if (MP_CMP(g->g, >, g->max)) {
+ mp_drop(g->q);
+ mp_drop(g->jq);
return (PGEN_ABORT);
+ }
rc = pfilt_create(&g->p, p);
mp_drop(p);
} break;