diff --git a/Makefile.in b/Makefile.in
index 44bfcbfcc..1a7359ea2 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -18,7 +18,7 @@
 #    59 Temple Place - Suite 330
 #    Boston, MA 02111-1307, USA
 #
-#ident "$Id: Makefile.in,v 1.63 2000/08/20 04:13:56 steve Exp $"
+#ident "$Id: Makefile.in,v 1.64 2000/09/02 20:54:20 steve Exp $"
 #
 #
 SHELL = /bin/sh
@@ -75,7 +75,7 @@ FF = nodangle.o synth.o syn-rules.o xnfio.o
 O = main.o cprop.o design_dump.o dup_expr.o elaborate.o elab_expr.o \
 elab_net.o elab_pexpr.o elab_scope.o elab_sig.o emit.o eval.o eval_tree.o \
 expr_synth.o functor.o lexor.o lexor_keyword.o link_const.o \
-mangle.o netlist.o \
+mangle.o netlist.o net_assign.o \
 net_design.o net_event.o net_force.o net_link.o net_proc.o net_scope.o \
 net_udp.o \
 pad_to_width.o \
diff --git a/design_dump.cc b/design_dump.cc
index 225657680..cf2c5a0e6 100644
--- a/design_dump.cc
+++ b/design_dump.cc
@@ -17,7 +17,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #if !defined(WINNT) && !defined(macintosh)
-#ident "$Id: design_dump.cc,v 1.94 2000/07/30 18:25:43 steve Exp $"
+#ident "$Id: design_dump.cc,v 1.95 2000/09/02 20:54:20 steve Exp $"
 #endif
 
 /*
@@ -217,23 +217,12 @@ void NetMux::dump_node(ostream&o, unsigned ind) const
       dump_obj_attr(o, ind+4);
 }
 
-void NetAssign::dump_node(ostream&o, unsigned ind) const
+void NetAssign_::dump_node(ostream&o, unsigned ind) const
 {
-      o << setw(ind) << "" << "Procedural assign (NetAssign): " << name();
+      o << setw(ind) << "" << "Procedural assign (NetAssign_): " << name();
       if (bmux())
 	    o << "[" << *bmux() << "]";
-      o << " = " << *rval() << endl;
-      dump_node_pins(o, ind+4);
-}
-
-void NetAssignNB::dump_node(ostream&o, unsigned ind) const
-{
-      if (bmux())
-	    o << setw(ind) << "" << "Procedural NB assign (NetAssignNB): "
-	      << name() << "[" << *bmux() << "] <= " << *rval() << endl;
-      else
-	    o << setw(ind) << "" << "Procedural NB assign (NetAssignNB): "
-	      << name() << " <= " << *rval() << endl;
+      o << endl;
       dump_node_pins(o, ind+4);
 }
 
@@ -438,16 +427,16 @@ void NetAssign::dump(ostream&o, unsigned ind) const
 {
       o << setw(ind) << "";
 
-      if (bmux()) {
-	    o << name() << "[" << *bmux() << "] = ";
-	    if (rise_time())
-		  o << "#" << rise_time() << " ";
+      if (l_val(0)->bmux()) {
+	    o << l_val(0)->name() << "[" << *l_val(0)->bmux() << "] = ";
+	    if (l_val(0)->rise_time())
+		  o << "#" << l_val(0)->rise_time() << " ";
 	    o << *rval() << ";" << endl;
 
       } else {
-	    o << name() << " = ";
-	    if (rise_time())
-		  o << "#" << rise_time() << " ";
+	    o << l_val(0)->name() << " = ";
+	    if (l_val(0)->rise_time())
+		  o << "#" << l_val(0)->rise_time() << " ";
 	    o << *rval() << ";" << endl;
       }
 }
@@ -456,16 +445,16 @@ void NetAssignNB::dump(ostream&o, unsigned ind) const
 {
       o << setw(ind) << "";
 
-      if (bmux()) {
-	    o << name() << "[" << *bmux() << "] <= ";
-	    if (rise_time())
-		  o << "#" << rise_time() << " ";
+      if (l_val(0)->bmux()) {
+	    o << l_val(0)->name() << "[" << *l_val(0)->bmux() << "] <= ";
+	    if (l_val(0)->rise_time())
+		  o << "#" << l_val(0)->rise_time() << " ";
 	    o << *rval() << ";" << endl;
 
       } else {
-	    o << name() << " <= ";
-	    if (rise_time())
-		  o << "#" << rise_time() << " ";
+	    o << l_val(0)->name() << " <= ";
+	    if (l_val(0)->rise_time())
+		  o << "#" << l_val(0)->rise_time() << " ";
 	    o << *rval() << ";" << endl;
       }
 }
@@ -978,6 +967,9 @@ void Design::dump(ostream&o) const
 
 /*
  * $Log: design_dump.cc,v $
+ * Revision 1.95  2000/09/02 20:54:20  steve
+ *  Rearrange NetAssign to make NetAssign_ separate.
+ *
  * Revision 1.94  2000/07/30 18:25:43  steve
  *  Rearrange task and function elaboration so that the
  *  NetTaskDef and NetFuncDef functions are created during
diff --git a/elab_net.cc b/elab_net.cc
index 1eb421ef6..c3a1cdc23 100644
--- a/elab_net.cc
+++ b/elab_net.cc
@@ -17,7 +17,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #if !defined(WINNT) && !defined(macintosh)
-#ident "$Id: elab_net.cc,v 1.44 2000/08/18 04:38:57 steve Exp $"
+#ident "$Id: elab_net.cc,v 1.45 2000/09/02 20:54:20 steve Exp $"
 #endif
 
 # include  "PExpr.h"
@@ -1178,7 +1178,7 @@ NetNet* PEIdent::elaborate_lnet(Design*des, const string&path) const
 	    verinum*mval = msb_->eval_const(des, path);
 	    if (mval == 0) {
 		  cerr << get_line() << ": index of " << text_ <<
-			" needs to be constant in this context." <<
+			" needs to be constant in l-value of assignment." <<
 			endl;
 		  des->errors += 1;
 		  return 0;
@@ -1286,7 +1286,7 @@ NetNet* PEIdent::elaborate_port(Design*des, NetScope*scope) const
 	    verinum*mval = msb_->eval_const(des, path);
 	    if (mval == 0) {
 		  cerr << get_line() << ": index of " << text_ <<
-			" needs to be constant in this context." <<
+			" needs to be constant in port context." <<
 			endl;
 		  des->errors += 1;
 		  return 0;
@@ -1662,6 +1662,9 @@ NetNet* PEUnary::elaborate_net(Design*des, const string&path,
 
 /*
  * $Log: elab_net.cc,v $
+ * Revision 1.45  2000/09/02 20:54:20  steve
+ *  Rearrange NetAssign to make NetAssign_ separate.
+ *
  * Revision 1.44  2000/08/18 04:38:57  steve
  *  Proper error messages when port direction is missing.
  *
diff --git a/elaborate.cc b/elaborate.cc
index 109fec933..96bf3f5dc 100644
--- a/elaborate.cc
+++ b/elaborate.cc
@@ -17,7 +17,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #if !defined(WINNT) && !defined(macintosh)
-#ident "$Id: elaborate.cc,v 1.183 2000/08/18 04:38:57 steve Exp $"
+#ident "$Id: elaborate.cc,v 1.184 2000/09/02 20:54:20 steve Exp $"
 #endif
 
 /*
@@ -745,7 +745,7 @@ NetNet* PAssign_::elaborate_lval(Design*des, const string&path,
 	/* Get the l-value, and assume that it is an identifier. */
       const PEIdent*id = dynamic_cast<const PEIdent*>(lval());
 
-	/* If the l-value is not a register, then make a structural
+	/* If the l-value is not a reg, then make a structural
 	   elaboration. Make a synthetic register that connects to the
 	   generated circuit and return that as the l-value. */
       if (id == 0) {
@@ -778,7 +778,7 @@ NetNet* PAssign_::elaborate_lval(Design*des, const string&path,
 
       if ((reg->type() != NetNet::REG) && (reg->type() != NetNet::INTEGER)) {
 	    cerr << get_line() << ": error: " << *lval() <<
-		  " is not a register." << endl;
+		  " is not a reg." << endl;
 	    des->errors += 1;
 	    return 0;
       }
@@ -946,20 +946,18 @@ NetProc* PAssign::elaborate(Design*des, const string&path) const
 	    n = des->local_symbol(path);
 	    NetAssign*a1 = new NetAssign(n, des, wid, rv);
 	    a1->set_line(*this);
-	    des->add_node(a1);
 
 	    for (unsigned idx = 0 ;  idx < wid ;  idx += 1)
-		  connect(a1->pin(idx), tmp->pin(idx));
+		  connect(a1->l_val(0)->pin(idx), tmp->pin(idx));
 
 	      /* Generate an assignment of the temporary to the r-value... */
 	    n = des->local_symbol(path);
 	    NetESignal*sig = new NetESignal(tmp);
 	    NetAssign*a2 = new NetAssign(n, des, wid, sig);
 	    a2->set_line(*this);
-	    des->add_node(a2);
 
 	    for (unsigned idx = 0 ;  idx < wid ;  idx += 1)
-		  connect(a2->pin(idx), reg->pin(idx));
+		  connect(a2->l_val(0)->pin(idx), reg->pin(idx));
 
 	      /* Generate the delay statement with the final
 		 assignment attached to it. If this is an event delay,
@@ -1006,7 +1004,7 @@ NetProc* PAssign::elaborate(Design*des, const string&path) const
 	    unsigned off = reg->sb_to_idx(lsb);
 	    assert((off+wid) <= reg->pin_count());
 	    for (unsigned idx = 0 ;  idx < wid ;  idx += 1)
-		  connect(cur->pin(idx), reg->pin(idx+off));
+		  connect(cur->l_val(0)->pin(idx), reg->pin(idx+off));
 
       } else {
 
@@ -1014,12 +1012,11 @@ NetProc* PAssign::elaborate(Design*des, const string&path) const
 	    cur = new NetAssign(des->local_symbol(path), des,
 				reg->pin_count(), mux, rv);
 	    for (unsigned idx = 0 ;  idx < reg->pin_count() ;  idx += 1)
-		  connect(cur->pin(idx), reg->pin(idx));
+		  connect(cur->l_val(0)->pin(idx), reg->pin(idx));
       }
 
 
       cur->set_line(*this);
-      des->add_node(cur);
 
       return cur;
 }
@@ -1105,7 +1102,7 @@ NetProc* PAssignNB::elaborate(Design*des, const string&path) const
 
 	    cur = new NetAssignNB(des->local_symbol(path), des, wid, rv);
 	    for (unsigned idx = 0 ;  idx < wid ;  idx += 1)
-		  connect(cur->pin(idx), reg->pin(reg->sb_to_idx(idx+lsb)));
+		  connect(cur->l_val(0)->pin(idx), reg->pin(reg->sb_to_idx(idx+lsb)));
 
       } else {
 
@@ -1117,20 +1114,19 @@ NetProc* PAssignNB::elaborate(Design*des, const string&path) const
 	    cur = new NetAssignNB(des->local_symbol(path), des,
 				  reg->pin_count(), mux, rv);
 	    for (unsigned idx = 0 ;  idx < reg->pin_count() ;  idx += 1)
-		  connect(cur->pin(idx), reg->pin(idx));
+		  connect(cur->l_val(0)->pin(idx), reg->pin(idx));
       }
 
 
       unsigned long rise_time, fall_time, decay_time;
       delay_.eval_delays(des, path, rise_time, fall_time, decay_time);
-      cur->rise_time(rise_time);
-      cur->fall_time(fall_time);
-      cur->decay_time(decay_time);
+      cur->l_val(0)->rise_time(rise_time);
+      cur->l_val(0)->fall_time(fall_time);
+      cur->l_val(0)->decay_time(decay_time);
 
 
 	/* All done with this node. mark its line number and check it in. */
       cur->set_line(*this);
-      des->add_node(cur);
       return cur;
 }
 
@@ -1445,8 +1441,7 @@ NetProc* PCallTask::elaborate_usr(Design*des, const string&path) const
 	    NetExpr*rv = parms_[idx]->elaborate_expr(des, scope);
 	    NetAssign*pr = new NetAssign("@", des, port->pin_count(), rv);
 	    for (unsigned pi = 0 ;  pi < port->pin_count() ;  pi += 1)
-		  connect(port->pin(pi), pr->pin(pi));
-	    des->add_node(pr);
+		  connect(port->pin(pi), pr->l_val(0)->pin(pi));
 	    block->append(pr);
       }
 
@@ -1535,9 +1530,8 @@ NetProc* PCallTask::elaborate_usr(Design*des, const string&path) const
 	      /* Generate the assignment statement. */
 	    NetAssign*ass = new NetAssign("@", des, val->pin_count(), pexp);
 	    for (unsigned pi = 0 ; pi < val->pin_count() ;  pi += 1)
-		  connect(val->pin(pi), ass->pin(pi));
+		  connect(val->pin(pi), ass->l_val(0)->pin(pi));
 
-	    des->add_node(ass);
 	    block->append(ass);
       }
 
@@ -2009,8 +2003,8 @@ NetProc* PForStatement::elaborate(Design*des, const string&path) const
       assert(sig);
       NetAssign*init = new NetAssign("@for-assign", des, sig->pin_count(),
 				     expr1_->elaborate_expr(des, scope));
-      for (unsigned idx = 0 ;  idx < init->pin_count() ;  idx += 1)
-	    connect(init->pin(idx), sig->pin(idx));
+      for (unsigned idx = 0 ;  idx < init->l_val(0)->pin_count() ;  idx += 1)
+	    connect(init->l_val(0)->pin(idx), sig->pin(idx));
 
       top->append(init);
 
@@ -2032,8 +2026,8 @@ NetProc* PForStatement::elaborate(Design*des, const string&path) const
       assert(sig);
       NetAssign*step = new NetAssign("@for-assign", des, sig->pin_count(),
 				     expr2_->elaborate_expr(des, scope));
-      for (unsigned idx = 0 ;  idx < step->pin_count() ;  idx += 1)
-	    connect(step->pin(idx), sig->pin(idx));
+      for (unsigned idx = 0 ;  idx < step->l_val(0)->pin_count() ;  idx += 1)
+	    connect(step->l_val(0)->pin(idx), sig->pin(idx));
 
       body->append(step);
 
@@ -2384,6 +2378,9 @@ Design* elaborate(const map<string,Module*>&modules,
 
 /*
  * $Log: elaborate.cc,v $
+ * Revision 1.184  2000/09/02 20:54:20  steve
+ *  Rearrange NetAssign to make NetAssign_ separate.
+ *
  * Revision 1.183  2000/08/18 04:38:57  steve
  *  Proper error messages when port direction is missing.
  *
diff --git a/emit.cc b/emit.cc
index e5117374a..5453575b4 100644
--- a/emit.cc
+++ b/emit.cc
@@ -17,7 +17,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #if !defined(WINNT) && !defined(macintosh)
-#ident "$Id: emit.cc,v 1.51 2000/08/14 04:39:56 steve Exp $"
+#ident "$Id: emit.cc,v 1.52 2000/09/02 20:54:20 steve Exp $"
 #endif
 
 /*
@@ -59,18 +59,12 @@ bool NetAddSub::emit_node(struct target_t*tgt) const
       return true;
 }
 
-bool NetAssign::emit_node(struct target_t*tgt) const
+bool NetAssign_::emit_node(struct target_t*tgt) const
 {
       tgt->net_assign(this);
       return true;
 }
 
-bool NetAssignNB::emit_node(struct target_t*tgt) const
-{
-      tgt->net_assign_nb(this);
-      return true;
-}
-
 bool NetCaseCmp::emit_node(struct target_t*tgt) const
 {
       tgt->net_case_cmp(this);
@@ -481,6 +475,9 @@ bool emit(const Design*des, const char*type)
 
 /*
  * $Log: emit.cc,v $
+ * Revision 1.52  2000/09/02 20:54:20  steve
+ *  Rearrange NetAssign to make NetAssign_ separate.
+ *
  * Revision 1.51  2000/08/14 04:39:56  steve
  *  add th t-dll functions for net_const, net_bufz and processes.
  *
diff --git a/net_assign.cc b/net_assign.cc
new file mode 100644
index 000000000..5157f4271
--- /dev/null
+++ b/net_assign.cc
@@ -0,0 +1,155 @@
+/*
+ * Copyright (c) 2000 Stephen Williams (steve@icarus.com)
+ *
+ *    This source code is free software; you can redistribute it
+ *    and/or modify it in source code form under the terms of the GNU
+ *    General Public License as published by the Free Software
+ *    Foundation; either version 2 of the License, or (at your option)
+ *    any later version.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    GNU General Public License for more details.
+ *
+ *    You should have received a copy of the GNU General Public License
+ *    along with this program; if not, write to the Free Software
+ *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
+ */
+#if !defined(WINNT) && !defined(macintosh)
+#ident "$Id: net_assign.cc,v 1.1 2000/09/02 20:54:20 steve Exp $"
+#endif
+
+# include  "netlist.h"
+
+/*
+ * NetAssign
+ */
+
+NetAssign_::NetAssign_(const string&n, unsigned w)
+: NetNode(n, w), bmux_(0)
+{
+      for (unsigned idx = 0 ;  idx < pin_count() ;  idx += 1) {
+	    pin(idx).set_dir(Link::OUTPUT);
+	    pin(idx).set_name("P", idx);
+      }
+
+}
+
+NetAssign_::~NetAssign_()
+{
+      if (bmux_) delete bmux_;
+}
+
+void NetAssign_::set_bmux(NetExpr*r)
+{
+      assert(bmux_ == 0);
+      bmux_ = r;
+}
+
+const NetExpr* NetAssign_::bmux() const
+{
+      return bmux_;
+}
+
+NetAssignBase::NetAssignBase(NetAssign_*lv, NetExpr*rv)
+: lval_(lv), rval_(rv)
+{
+}
+
+NetAssignBase::~NetAssignBase()
+{
+      if (rval_) delete rval_;
+      if (lval_) delete lval_;
+}
+
+NetExpr* NetAssignBase::rval()
+{
+      return rval_;
+}
+
+const NetExpr* NetAssignBase::rval() const
+{
+      return rval_;
+}
+
+void NetAssignBase::set_rval(NetExpr*r)
+{
+      if (rval_) delete rval_;
+      rval_ = r;
+}
+
+NetAssign_* NetAssignBase::l_val(unsigned idx)
+{
+      assert(idx == 0);
+      return lval_;
+}
+
+const NetAssign_* NetAssignBase::l_val(unsigned idx) const
+{
+      assert(idx == 0);
+      return lval_;
+}
+
+
+NetAssign::NetAssign(const string&n, Design*des, unsigned w, NetExpr*rv)
+: NetAssignBase(new NetAssign_(n, w), rv)
+{
+      des->add_node(l_val(0));
+}
+
+NetAssign::NetAssign(const string&n, Design*des, unsigned w,
+		     NetExpr*mu, NetExpr*rv)
+: NetAssignBase(new NetAssign_(n, w), rv)
+{
+      des->add_node(l_val(0));
+      bool flag = rv->set_width(1);
+      if (flag == false) {
+	    cerr << rv->get_line() << ": Expression bit width" <<
+		  " conflicts with l-value bit width." << endl;
+	    des->errors += 1;
+      }
+
+      l_val(0)->set_bmux(mu);
+}
+
+NetAssign::~NetAssign()
+{
+}
+
+NetAssignNB::NetAssignNB(const string&n, Design*des, unsigned w, NetExpr*rv)
+: NetAssignBase(new NetAssign_(n, w), rv)
+{
+      if (rval()->expr_width() < w) {
+	    cerr << rval()->get_line() << ": Expression bit width (" <<
+		  rval()->expr_width() << ") conflicts with l-value "
+		  "bit width (" << w << ")." << endl;
+	    des->errors += 1;
+      }
+}
+
+NetAssignNB::NetAssignNB(const string&n, Design*des, unsigned w,
+			 NetExpr*mu, NetExpr*rv)
+: NetAssignBase(new NetAssign_(n, w), rv)
+{
+      bool flag = rval()->set_width(1);
+      if (flag == false) {
+	    cerr << rval()->get_line() << ": Expression bit width" <<
+		  " conflicts with l-value bit width." << endl;
+	    des->errors += 1;
+      }
+
+      l_val(0)->set_bmux(mu);
+}
+
+NetAssignNB::~NetAssignNB()
+{
+}
+
+/*
+ * $Log: net_assign.cc,v $
+ * Revision 1.1  2000/09/02 20:54:20  steve
+ *  Rearrange NetAssign to make NetAssign_ separate.
+ *
+ */
+
diff --git a/netlist.cc b/netlist.cc
index 5e6cf22b4..e0be0f495 100644
--- a/netlist.cc
+++ b/netlist.cc
@@ -17,7 +17,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #if !defined(WINNT) && !defined(macintosh)
-#ident "$Id: netlist.cc,v 1.134 2000/08/27 15:51:50 steve Exp $"
+#ident "$Id: netlist.cc,v 1.135 2000/09/02 20:54:20 steve Exp $"
 #endif
 
 # include  <cassert>
@@ -1370,111 +1370,6 @@ const Link& NetRamDq::pin_Q(unsigned idx) const
       return pin(3+awidth_+width()+idx);
 }
 
-/*
- * NetAssign
- */
-
-NetAssign_::NetAssign_(const string&n, unsigned w)
-: NetNode(n, w), rval_(0), bmux_(0)
-{
-      for (unsigned idx = 0 ;  idx < pin_count() ;  idx += 1) {
-	    pin(idx).set_dir(Link::OUTPUT);
-	    pin(idx).set_name("P", idx);
-      }
-
-}
-
-NetAssign_::~NetAssign_()
-{
-      if (rval_) delete rval_;
-      if (bmux_) delete bmux_;
-}
-
-void NetAssign_::set_rval(NetExpr*r)
-{
-      if (rval_) delete rval_;
-      rval_ = r;
-}
-
-void NetAssign_::set_bmux(NetExpr*r)
-{
-      assert(bmux_ == 0);
-      bmux_ = r;
-}
-
-NetExpr* NetAssign_::rval()
-{
-      return rval_;
-}
-
-const NetExpr* NetAssign_::rval() const
-{
-      return rval_;
-}
-
-const NetExpr* NetAssign_::bmux() const
-{
-      return bmux_;
-}
-
-NetAssign::NetAssign(const string&n, Design*des, unsigned w, NetExpr*rv)
-: NetAssign_(n, w)
-{
-      set_rval(rv);
-}
-
-NetAssign::NetAssign(const string&n, Design*des, unsigned w,
-		     NetExpr*mu, NetExpr*rv)
-: NetAssign_(n, w)
-{
-      bool flag = rv->set_width(1);
-      if (flag == false) {
-	    cerr << rv->get_line() << ": Expression bit width" <<
-		  " conflicts with l-value bit width." << endl;
-	    des->errors += 1;
-      }
-
-      set_rval(rv);
-      set_bmux(mu);
-}
-
-NetAssign::~NetAssign()
-{
-}
-
-NetAssignNB::NetAssignNB(const string&n, Design*des, unsigned w, NetExpr*rv)
-: NetAssign_(n, w)
-{
-      if (rv->expr_width() < w) {
-	    cerr << rv->get_line() << ": Expression bit width (" <<
-		  rv->expr_width() << ") conflicts with l-value "
-		  "bit width (" << w << ")." << endl;
-	    des->errors += 1;
-      }
-
-      set_rval(rv);
-}
-
-NetAssignNB::NetAssignNB(const string&n, Design*des, unsigned w,
-			 NetExpr*mu, NetExpr*rv)
-: NetAssign_(n, w)
-{
-      bool flag = rv->set_width(1);
-      if (flag == false) {
-	    cerr << rv->get_line() << ": Expression bit width" <<
-		  " conflicts with l-value bit width." << endl;
-	    des->errors += 1;
-      }
-
-      set_rval(rv);
-      set_bmux(mu);
-}
-
-NetAssignNB::~NetAssignNB()
-{
-}
-
-
 NetAssignMem_::NetAssignMem_(NetMemory*m, NetExpr*i, NetExpr*r)
 : mem_(m), index_(i), rval_(r)
 {
@@ -2467,6 +2362,9 @@ bool NetUDP::sequ_glob_(string input, char output)
 
 /*
  * $Log: netlist.cc,v $
+ * Revision 1.135  2000/09/02 20:54:20  steve
+ *  Rearrange NetAssign to make NetAssign_ separate.
+ *
  * Revision 1.134  2000/08/27 15:51:50  steve
  *  t-dll iterates signals, and passes them to the
  *  target module.
diff --git a/netlist.h b/netlist.h
index b5a639ffd..5c848a8a0 100644
--- a/netlist.h
+++ b/netlist.h
@@ -19,7 +19,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #if !defined(WINNT) && !defined(macintosh)
-#ident "$Id: netlist.h,v 1.158 2000/08/27 15:51:50 steve Exp $"
+#ident "$Id: netlist.h,v 1.159 2000/09/02 20:54:20 steve Exp $"
 #endif
 
 /*
@@ -1108,46 +1108,75 @@ class NetProc : public LineInfo {
 };
 
 /*
- * This is a procedural assignment. The lval is a register, and the
- * assignment happens when the code is executed by the design. The
- * node part of the NetAssign has as many pins as the width of the
- * lvalue object and represents the elaborated lvalue. Thus, this
- * appears as a procedural statement AND a structural node. The
- * LineInfo is the location of the assignment statement in the source.
+ * Procedural assignment is broken into a suite of classes. These
+ * classes represent the various aspects of the assignment statement
+ * in behavioral code. (The continuous assignment is *not*
+ * represented here.)
+ *
+ * The NetAssignBase carries the common aspects of an assignment,
+ * including the r-value. This class has no cares of blocking vs
+ * non-blocking, however it carries nearly all the other properties
+ * of the assignment statement. It is abstract because it does not
+ * differentiate the virtual behaviors.
+ *
+ * The NetAssign and NetAssignNB classes are the concrete classes that
+ * give the assignment its final, precise meaning. These classes fill
+ * in the NetProc behaviors.
+ *
+ * The l-value of the assignment is a collection of NetAssign_
+ * objects. These are nodes that connect to the structural netlist
+ * where the assignment has its effect. The NetAssign_ class is not to
+ * be derived from.
  *
  * NOTE: The elaborator will make an effort to match the width of the
- * r-value to the with of the assign node, but targets and functions
+ * r-value to the with of the l-value, but targets and functions
  * should know that this is not a guarantee.
  */
 
-class NetAssign_ : public NetProc, public NetNode {
+class NetAssign_ : public NetNode {
 
     public:
-
-	// This is the (procedural) value that is to be assigned when
-	// the assignment is executed.
-      NetExpr*rval();
-      const NetExpr*rval() const;
+      NetAssign_(const string&n, unsigned w);
+      ~NetAssign_();
 
 	// If this expression exists, then only a single bit is to be
 	// set from the rval, and the value of this expression selects
 	// the pin that gets the value.
       const NetExpr*bmux() const;
 
-      void set_rval(NetExpr*);
-
-    protected:
-      NetAssign_(const string&n, unsigned w);
-      virtual ~NetAssign_() =0;
 
       void set_bmux(NetExpr*);
 
+      virtual bool emit_node(struct target_t*) const;
+      virtual void dump_node(ostream&, unsigned ind) const;
+
     private:
-      NetExpr*rval_;
       NetExpr*bmux_;
 };
 
-class NetAssign  : public NetAssign_ {
+class NetAssignBase : public NetProc {
+
+    public:
+      NetAssignBase(NetAssign_*lv, NetExpr*rv);
+      virtual ~NetAssignBase() =0;
+
+	// This is the (procedural) value that is to be assigned when
+	// the assignment is executed.
+      NetExpr*rval();
+      const NetExpr*rval() const;
+
+      void set_rval(NetExpr*);
+
+      NetAssign_* l_val(unsigned);
+      const NetAssign_* l_val(unsigned) const;
+
+    private:
+      NetAssign_*lval_;
+      NetExpr   *rval_;
+};
+
+class NetAssign : public NetAssignBase {
+
     public:
       explicit NetAssign(const string&, Design*des, unsigned w, NetExpr*rv);
       explicit NetAssign(const string&, Design*des, unsigned w,
@@ -1155,18 +1184,13 @@ class NetAssign  : public NetAssign_ {
       ~NetAssign();
 
       virtual bool emit_proc(struct target_t*) const;
-      virtual bool emit_node(struct target_t*) const;
       virtual int match_proc(struct proc_match_t*);
       virtual void dump(ostream&, unsigned ind) const;
-      virtual void dump_node(ostream&, unsigned ind) const;
 
     private:
 };
 
-/*
- * ... and this is a non-blocking version of above.
- */
-class NetAssignNB  : public NetAssign_ {
+class NetAssignNB  : public NetAssignBase {
     public:
       explicit NetAssignNB(const string&, Design*des, unsigned w, NetExpr*rv);
       explicit NetAssignNB(const string&, Design*des, unsigned w,
@@ -1175,10 +1199,8 @@ class NetAssignNB  : public NetAssign_ {
 
 
       virtual bool emit_proc(struct target_t*) const;
-      virtual bool emit_node(struct target_t*) const;
       virtual int match_proc(struct proc_match_t*);
       virtual void dump(ostream&, unsigned ind) const;
-      virtual void dump_node(ostream&, unsigned ind) const;
 
     private:
 };
@@ -2726,6 +2748,9 @@ extern ostream& operator << (ostream&, NetNet::Type);
 
 /*
  * $Log: netlist.h,v $
+ * Revision 1.159  2000/09/02 20:54:20  steve
+ *  Rearrange NetAssign to make NetAssign_ separate.
+ *
  * Revision 1.158  2000/08/27 15:51:50  steve
  *  t-dll iterates signals, and passes them to the
  *  target module.
diff --git a/syn-rules.y b/syn-rules.y
index 8caafe8c1..722e8e5ab 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 1.8 2000/08/01 02:48:42 steve Exp $"
+#ident "$Id: syn-rules.y,v 1.9 2000/09/02 20:54:21 steve Exp $"
 #endif
 
 /*
@@ -38,7 +38,7 @@
 struct syn_token_t {
       int token;
 
-      NetAssign_*assign;
+      NetAssignBase*assign;
       NetAssignMem_*assign_mem;
       NetProcTop*top;
       NetEvWait*evwait;
@@ -54,10 +54,10 @@ static void yyerror(const char*);
 static Design*des_;
 
 static void make_DFF_CE(Design*des, NetProcTop*top, NetEvWait*wclk,
-			NetEvent*eclk, NetExpr*cexp, NetAssign_*asn);
+			NetEvent*eclk, NetExpr*cexp, NetAssignBase*asn);
 static void make_RAM_CE(Design*des, NetProcTop*top, NetEvWait*wclk,
 			NetEvent*eclk, NetExpr*cexp, NetAssignMem_*asn);
-static void make_initializer(Design*des, NetProcTop*top, NetAssign_*asn);
+static void make_initializer(Design*des, NetProcTop*top, NetAssignBase*asn);
 
 %}
 
@@ -131,7 +131,7 @@ start
 
   /* Various actions. */
 static void make_DFF_CE(Design*des, NetProcTop*top, NetEvWait*wclk,
-			NetEvent*eclk, NetExpr*cexp, NetAssign_*asn)
+			NetEvent*eclk, NetExpr*cexp, NetAssignBase*asn)
 {
       NetEvProbe*pclk = eclk->probe(0);
       NetESignal*d = dynamic_cast<NetESignal*> (asn->rval());
@@ -139,11 +139,11 @@ static void make_DFF_CE(Design*des, NetProcTop*top, NetEvWait*wclk,
 
       assert(d);
 
-      NetFF*ff = new NetFF(asn->name(), asn->pin_count());
+      NetFF*ff = new NetFF(asn->l_val(0)->name(), asn->l_val(0)->pin_count());
 
       for (unsigned idx = 0 ;  idx < ff->width() ;  idx += 1) {
 	    connect(ff->pin_Data(idx), d->pin(idx));
-	    connect(ff->pin_Q(idx), asn->pin(idx));
+	    connect(ff->pin_Q(idx), asn->l_val(0)->pin(idx));
       }
 
       connect(ff->pin_Clock(), pclk->pin(0));
@@ -198,16 +198,16 @@ static void make_RAM_CE(Design*des, NetProcTop*top, NetEvWait*wclk,
  * the initial value for the link and get rid of the assignment
  * process.
  */
-static void make_initializer(Design*des, NetProcTop*top, NetAssign_*asn)
+static void make_initializer(Design*des, NetProcTop*top, NetAssignBase*asn)
 {
       NetESignal*rsig = dynamic_cast<NetESignal*> (asn->rval());
       assert(rsig);
 
-      for (unsigned idx = 0 ;  idx < asn->pin_count() ;  idx += 1) {
+      for (unsigned idx = 0 ;  idx < asn->l_val(0)->pin_count() ;  idx += 1) {
 
 	    verinum::V bit = driven_value(rsig->pin(idx));
 
-	    Nexus*nex = asn->pin(idx).nexus();
+	    Nexus*nex = asn->l_val(0)->pin(idx).nexus();
 	    for (Link*cur = nex->first_nlink()
 		       ;  cur ;  cur = cur->next_nlink()) {
 
@@ -237,7 +237,7 @@ struct tokenize : public proc_match_t {
       {
 	    syn_token_t*cur;
 	    cur = new syn_token_t;
-	    cur->token = dev->bmux() ? S_ASSIGN_MUX : S_ASSIGN;
+	    cur->token = dev->l_val(0)->bmux() ? S_ASSIGN_MUX : S_ASSIGN;
 	    cur->assign = dev;
 	    cur->next_ = 0;
 	    last_->next_ = cur;
@@ -249,7 +249,7 @@ struct tokenize : public proc_match_t {
       {
 	    syn_token_t*cur;
 	    cur = new syn_token_t;
-	    cur->token = dev->bmux() ? S_ASSIGN_MUX : S_ASSIGN;
+	    cur->token = dev->l_val(0)->bmux() ? S_ASSIGN_MUX : S_ASSIGN;
 	    cur->assign = dev;
 	    cur->next_ = 0;
 	    last_->next_ = cur;
diff --git a/t-vvm.cc b/t-vvm.cc
index 43e099eba..6f528a3a4 100644
--- a/t-vvm.cc
+++ b/t-vvm.cc
@@ -17,7 +17,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #if !defined(WINNT) && !defined(macintosh)
-#ident "$Id: t-vvm.cc,v 1.169 2000/08/20 17:49:04 steve Exp $"
+#ident "$Id: t-vvm.cc,v 1.170 2000/09/02 20:54:21 steve Exp $"
 #endif
 
 # include  <iostream>
@@ -166,7 +166,6 @@ class target_vvm : public target_t {
       virtual void udp(const NetUDP*);
       virtual void udp_comb(const NetUDP_COMB*);
               void udp_sequ_(ostream&os, const NetUDP*);
-      virtual void net_assign_nb(const NetAssignNB*);
       virtual void net_case_cmp(const NetCaseCmp*);
       virtual bool net_cassign(const NetCAssign*);
       virtual bool net_const(const NetConst*);
@@ -1970,10 +1969,6 @@ void target_vvm::udp_sequ_(ostream&os, const NetUDP*gate)
 
 }
 
-void target_vvm::net_assign_nb(const NetAssignNB*net)
-{
-}
-
 void target_vvm::net_case_cmp(const NetCaseCmp*gate)
 {
       string mname = mangle(gate->name());
@@ -2157,7 +2152,7 @@ void target_vvm::proc_assign(const NetAssign*net)
 
 	    const verinum value = rc->value();
 
-	    if (net->bmux()) {
+	    if (net->l_val(0)->bmux()) {
 
 		    // This is a bit select. Assign the low bit of the
 		    // constant to the selected bit of the lval.
@@ -2166,14 +2161,14 @@ void target_vvm::proc_assign(const NetAssign*net)
 						 Link::STRONG,
 						 Link::STRONG);
 
-		  string bval = emit_proc_rval(this, net->bmux());
+		  string bval = emit_proc_rval(this, net->l_val(0)->bmux());
 
 		  defn << "      switch (" << bval
 		       << ".as_unsigned()) {" << endl;
 
-		  for (unsigned idx = 0; idx < net->pin_count(); idx += 1) {
+		  for (unsigned idx = 0; idx < net->l_val(0)->pin_count(); idx += 1) {
 
-			string nexus = net->pin(idx).nexus()->name();
+			string nexus = net->l_val(0)->pin(idx).nexus()->name();
 			unsigned ncode = nexus_wire_map[nexus];
 
 			defn << "      case " << idx << ":" << endl;
@@ -2188,8 +2183,8 @@ void target_vvm::proc_assign(const NetAssign*net)
 		  return;
 	    }
 
-	    for (unsigned idx = 0 ;  idx < net->pin_count() ;  idx += 1) {
-		  string nexus = net->pin(idx).nexus()->name();
+	    for (unsigned idx = 0 ;  idx < net->l_val(0)->pin_count() ;  idx += 1) {
+		  string nexus = net->l_val(0)->pin(idx).nexus()->name();
 		  unsigned ncode = nexus_wire_map[nexus];
 
 		  verinum::V val = idx < value.len() 
@@ -2219,12 +2214,12 @@ void target_vvm::proc_assign(const NetAssign*net)
 
       if (const NetESignal*rs = dynamic_cast<const NetESignal*>(net->rval())) {
 
-	    if (net->pin_count() > rs->pin_count()) {
+	    if (net->l_val(0)->pin_count() > rs->pin_count()) {
 		  rval = emit_proc_rval(this, net->rval());
 
 	    } else {
-		  assert((net->pin_count() <= rs->pin_count())
-			 || (net->bmux() && (rs->pin_count() >= 1)));
+		  assert((net->l_val(0)->pin_count() <= rs->pin_count())
+			 || (net->l_val(0)->bmux() && (rs->pin_count() >= 1)));
 		  rval = mangle(rs->name()) + ".bits";
 	    }
 
@@ -2242,17 +2237,17 @@ void target_vvm::proc_assign(const NetAssign*net)
 	   l-value. Otherwise, generate code for a complete
 	   assignment. */
 
-      if (net->bmux()) {
+      if (net->l_val(0)->bmux()) {
 
 	      // This is a bit select. Assign the low bit of the rval
 	      // to the selected bit of the lval.
-	    string bval = emit_proc_rval(this, net->bmux());
+	    string bval = emit_proc_rval(this, net->l_val(0)->bmux());
 
 	    defn << "      switch (" << bval << ".as_unsigned()) {" << endl;
 
-	    for (unsigned idx = 0 ;  idx < net->pin_count() ;  idx += 1) {
+	    for (unsigned idx = 0 ;  idx < net->l_val(0)->pin_count() ;  idx += 1) {
 
-		  string nexus = net->pin(idx).nexus()->name();
+		  string nexus = net->l_val(0)->pin(idx).nexus()->name();
 		  unsigned ncode = nexus_wire_map[nexus];
 
 		  defn << "      case " << idx << ":" << endl;
@@ -2266,19 +2261,19 @@ void target_vvm::proc_assign(const NetAssign*net)
 	    defn << "      }" << endl;
 
       } else {
-	    unsigned min_count = net->pin_count();
+	    unsigned min_count = net->l_val(0)->pin_count();
 	    if (net->rval()->expr_width() < min_count)
 		  min_count = net->rval()->expr_width();
 
 	    for (unsigned idx = 0 ;  idx < min_count ;  idx += 1) {
-		  string nexus = net->pin(idx).nexus()->name();
+		  string nexus = net->l_val(0)->pin(idx).nexus()->name();
 		  unsigned ncode = nexus_wire_map[nexus];
 		  defn << "      nexus_wire_table["<<ncode<<"].reg_assign("
 		       << rval << "[" << idx << "]);" << endl;
 	    }
 
-	    for (unsigned idx = min_count; idx < net->pin_count(); idx += 1) {
-		  string nexus = net->pin(idx).nexus()->name();
+	    for (unsigned idx = min_count; idx < net->l_val(0)->pin_count(); idx += 1) {
+		  string nexus = net->l_val(0)->pin(idx).nexus()->name();
 		  unsigned ncode = nexus_wire_map[nexus];
 		  defn << "      nexus_wire_table["<<ncode<<"]"
 		       << ".reg_assign(St0);" << endl;
@@ -2319,9 +2314,9 @@ void target_vvm::proc_assign_mem(const NetAssignMem*amem)
 void target_vvm::proc_assign_nb(const NetAssignNB*net)
 {
       string rval = emit_proc_rval(this, net->rval());
-      const unsigned long delay = net->rise_time();
+      const unsigned long delay = net->l_val(0)->rise_time();
 
-      if (net->bmux()) {
+      if (net->l_val(0)->bmux()) {
 	      /* If the l-value has a bit select, set the output bit
 		 to only the desired bit. Evaluate the index and use
 		 that to drive a switch statement.
@@ -2330,11 +2325,11 @@ void target_vvm::proc_assign_nb(const NetAssignNB*net)
 		 better generating a demux device and doing the assign
 		 to the device input. Food for thought. */
 
-	    string bval = emit_proc_rval(this, net->bmux());
+	    string bval = emit_proc_rval(this, net->l_val(0)->bmux());
 	    defn << "      switch (" << bval << ".as_unsigned()) {" << endl;
 
-	    for (unsigned idx = 0 ;  idx < net->pin_count() ;  idx += 1) {
-		  string nexus = net->pin(idx).nexus()->name();
+	    for (unsigned idx = 0 ;  idx < net->l_val(0)->pin_count() ;  idx += 1) {
+		  string nexus = net->l_val(0)->pin(idx).nexus()->name();
 		  unsigned ncode = nexus_wire_map[nexus];
 
 		  defn << "      case " << idx << ":" << endl;
@@ -2347,8 +2342,8 @@ void target_vvm::proc_assign_nb(const NetAssignNB*net)
 	    defn << "      }" << endl;
 
       } else {
-	    for (unsigned idx = 0 ; idx < net->pin_count() ;  idx += 1) {
-		  string nexus = net->pin(idx).nexus()->name();
+	    for (unsigned idx = 0 ; idx < net->l_val(0)->pin_count() ;  idx += 1) {
+		  string nexus = net->l_val(0)->pin(idx).nexus()->name();
 		  unsigned ncode = nexus_wire_map[nexus];
 		  defn << "      vvm_delayed_assign(nexus_wire_table["
 		       << ncode << "], " << rval << "[" << idx << "], "
@@ -3117,6 +3112,9 @@ extern const struct target tgt_vvm = {
 };
 /*
  * $Log: t-vvm.cc,v $
+ * Revision 1.170  2000/09/02 20:54:21  steve
+ *  Rearrange NetAssign to make NetAssign_ separate.
+ *
  * Revision 1.169  2000/08/20 17:49:04  steve
  *  Clean up warnings and portability issues.
  *
diff --git a/target.cc b/target.cc
index 00bd2d502..e17fe5f4c 100644
--- a/target.cc
+++ b/target.cc
@@ -17,7 +17,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #if !defined(WINNT) && !defined(macintosh)
-#ident "$Id: target.cc,v 1.45 2000/08/27 15:51:51 steve Exp $"
+#ident "$Id: target.cc,v 1.46 2000/09/02 20:54:21 steve Exp $"
 #endif
 
 # include  "target.h"
@@ -126,14 +126,10 @@ void target_t::lpm_ram_dq(const NetRamDq*)
 	    "Unhandled NetRamDq." << endl;
 }
 
-void target_t::net_assign(const NetAssign*)
-{
-}
-
-void target_t::net_assign_nb(const NetAssignNB*)
+void target_t::net_assign(const NetAssign_*)
 {
       cerr << "target (" << typeid(*this).name() <<  "): "
-	    "Unhandled non-blocking assignment node." << endl;
+	    "Unhandled assignment node." << endl;
 }
 
 void target_t::net_case_cmp(const NetCaseCmp*)
@@ -392,6 +388,9 @@ void expr_scan_t::expr_binary(const NetEBinary*ex)
 
 /*
  * $Log: target.cc,v $
+ * Revision 1.46  2000/09/02 20:54:21  steve
+ *  Rearrange NetAssign to make NetAssign_ separate.
+ *
  * Revision 1.45  2000/08/27 15:51:51  steve
  *  t-dll iterates signals, and passes them to the
  *  target module.
diff --git a/target.h b/target.h
index 30905f9d5..ccec16f2f 100644
--- a/target.h
+++ b/target.h
@@ -19,7 +19,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #if !defined(WINNT) && !defined(macintosh)
-#ident "$Id: target.h,v 1.44 2000/08/27 15:51:51 steve Exp $"
+#ident "$Id: target.h,v 1.45 2000/09/02 20:54:21 steve Exp $"
 #endif
 
 # include  "netlist.h"
@@ -87,8 +87,7 @@ struct target_t {
       virtual bool bufz(const NetBUFZ*);
       virtual void udp(const NetUDP*);
       virtual void udp_comb(const NetUDP_COMB*);
-      virtual void net_assign(const NetAssign*);
-      virtual void net_assign_nb(const NetAssignNB*);
+      virtual void net_assign(const NetAssign_*);
       virtual void net_case_cmp(const NetCaseCmp*);
       virtual bool net_cassign(const NetCAssign*);
       virtual bool net_const(const NetConst*);
@@ -160,6 +159,9 @@ extern const struct target *target_table[];
 
 /*
  * $Log: target.h,v $
+ * Revision 1.45  2000/09/02 20:54:21  steve
+ *  Rearrange NetAssign to make NetAssign_ separate.
+ *
  * Revision 1.44  2000/08/27 15:51:51  steve
  *  t-dll iterates signals, and passes them to the
  *  target module.