diff --git a/syn-rules.y b/syn-rules.y
index cdfbafd88..d618b5b64 100644
--- a/syn-rules.y
+++ b/syn-rules.y
@@ -19,7 +19,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #if !defined(WINNT) && !defined(macintosh)
-#ident "$Id: syn-rules.y,v 1.10 2000/11/11 00:03:36 steve Exp $"
+#ident "$Id: syn-rules.y,v 1.11 2000/11/22 21:18:42 steve Exp $"
 #endif
 
 /*
@@ -133,10 +133,17 @@ start
 static void make_DFF_CE(Design*des, NetProcTop*top, NetEvWait*wclk,
 			NetEvent*eclk, NetExpr*cexp, NetAssignBase*asn)
 {
+      assert(asn);
+
       NetEvProbe*pclk = eclk->probe(0);
       NetESignal*d = dynamic_cast<NetESignal*> (asn->rval());
       NetNet*ce = cexp? cexp->synthesize(des) : 0;
 
+      if (d == 0) {
+	    cerr << asn->get_line() << ": internal error: "
+		 << " not a simple signal? " << *asn->rval() << endl;
+      }
+
       assert(d);
 
       NetFF*ff = new NetFF(top->scope(), asn->l_val(0)->name(),
diff --git a/synth.cc b/synth.cc
index d28c95fe7..149dd6a3b 100644
--- a/synth.cc
+++ b/synth.cc
@@ -17,7 +17,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #if !defined(WINNT) && !defined(macintosh)
-#ident "$Id: synth.cc,v 1.10 2000/05/13 20:55:47 steve Exp $"
+#ident "$Id: synth.cc,v 1.11 2000/11/22 21:18:42 steve Exp $"
 #endif
 
 # include  "functor.h"
@@ -42,6 +42,7 @@ class do_expr  : public proc_match_t {
       Design*des_;
 
       virtual int assign(NetAssign*);
+      virtual int assign_nb(NetAssignNB*);
       virtual int event_wait(NetEvWait*);
 	//virtual int assign_mem(NetAssignMem*);
       virtual int condit(NetCondit*);
@@ -63,6 +64,21 @@ int do_expr::assign(NetAssign*stmt)
       return 0;
 }
 
+int do_expr::assign_nb(NetAssignNB*stmt)
+{
+      if (dynamic_cast<NetESignal*>(stmt->rval()))
+	    return 0;
+
+      NetNet*tmp = stmt->rval()->synthesize(des_);
+      if (tmp == 0)
+	    return 0;
+
+      NetESignal*tmpe = new NetESignal(tmp);
+      stmt->set_rval(tmpe);
+
+      return 0;
+}
+
 int do_expr::condit(NetCondit*stmt)
 {
 	/* synthesize the condition expression, if necessary. */
@@ -145,6 +161,9 @@ void synth(Design*des)
 
 /*
  * $Log: synth.cc,v $
+ * Revision 1.11  2000/11/22 21:18:42  steve
+ *  synthesize the rvalue of <= statements.
+ *
  * Revision 1.10  2000/05/13 20:55:47  steve
  *  Use yacc based synthesizer.
  *