From 8615bf7e3cefc66290450159a60a30a6c2ac862b Mon Sep 17 00:00:00 2001
From: mdw <mdw>
Date: Sat, 1 Jul 2000 11:09:20 +0000
Subject: [PATCH] (pgen_gcd): Bug fix -- check the GCDs of the right things
 when deciding whether to abort.

---
 pgen-gcd.c | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/pgen-gcd.c b/pgen-gcd.c
index cd23c37..35b770a 100644
--- a/pgen-gcd.c
+++ b/pgen-gcd.c
@@ -1,6 +1,6 @@
 /* -*-c-*-
  *
- * $Id: pgen-gcd.c,v 1.1 2000/06/17 11:51:53 mdw Exp $
+ * $Id: pgen-gcd.c,v 1.2 2000/07/01 11:09:20 mdw Exp $
  *
  * Prime search stepper ensuring a low GCD for %$(p - 1)/2$%
  *
@@ -30,6 +30,10 @@
 /*----- Revision history --------------------------------------------------* 
  *
  * $Log: pgen-gcd.c,v $
+ * Revision 1.2  2000/07/01 11:09:20  mdw
+ * (pgen_gcd): Bug fix -- check the GCDs of the right things when deciding
+ * whether to abort.
+ *
  * 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.
@@ -52,16 +56,24 @@ int pgen_gcdstep(int rq, pgen_event *ev, void *p)
 
     /* --- 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;
-- 
2.11.0