Generalize the evaluation of floating point delays, and

get it working with delay assignment statements.

 Allow parameters to be referenced by hierarchical name.

Makefile.in

@@ -16,7 +16,7 @@
 #    59 Temple Place - Suite 330
 #    Boston, MA 02111-1307, USA
 #
-#ident "$Id: Makefile.in,v 1.89 2001/01/09 03:11:27 steve Exp $"
+#ident "$Id: Makefile.in,v 1.90 2001/01/14 23:04:55 steve Exp $"
 #
 #
 SHELL = /bin/sh
@@ -96,7 +96,7 @@ 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_lval.o elab_net.o elab_anet.o elab_pexpr.o elab_scope.o \
-elab_sig.o emit.o eval.o \
+elab_sig.o emit.o eval.o eval_rconst.o \
 eval_tree.o expr_synth.o functor.o lexor.o lexor_keyword.o link_const.o \
 mangle.o netlist.o net_assign.o \
 net_design.o net_event.o net_force.o net_link.o net_modulo.o net_proc.o \

PDelays.cc

@@ -17,7 +17,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #if !defined(WINNT) && !defined(macintosh)
-#ident "$Id: PDelays.cc,v 1.2 2000/02/23 02:56:53 steve Exp $"
+#ident "$Id: PDelays.cc,v 1.3 2001/01/14 23:04:55 steve Exp $"
 #endif
 
 # include  "PDelays.h"
@@ -52,30 +52,49 @@ void PDelays::set_delays(const svector<PExpr*>*del)
 	    delay_[idx] = (*del)[idx];
 }
 
-void PDelays::eval_delays(Design*des, const string&path,
+static unsigned long calculate_val(Design*des, const NetScope*scope,
-			unsigned long&rise_time,
+				   const PExpr*expr)
-			unsigned long&fall_time,
-			unsigned long&decay_time) const
 {
-      verinum*dv;
+      assert(expr);
+      unsigned long val;
+
+      int shift = scope->time_unit() - des->get_precision();
+
+      if (verireal*dr = expr->eval_rconst(des, scope)) {
+	    val = dr->as_long(shift);
+	    delete dr;
+
+      } else {
+	    verinum*dv = expr->eval_const(des, scope->name());
+	    assert(dv);
+	    val = dv->as_ulong();
+	    val = des->scale_to_precision(val, scope);
+	    delete dv;
+      }
+
+      return val;
+}
+
+void PDelays::eval_delays(Design*des, const string&path,
+			  unsigned long&rise_time,
+			  unsigned long&fall_time,
+			  unsigned long&decay_time) const
+{
+      NetScope*scope = des->find_scope(path);
+      assert(scope);
+
+      int shift = scope->time_unit() - des->get_precision();
+
 
       if (delay_[0]) {
-	    dv = delay_[0]->eval_const(des, path);
+	    rise_time = calculate_val(des, scope, delay_[0]);
-	    assert(dv);
-	    rise_time = dv->as_ulong();
-	    delete dv;
 
 	    if (delay_[1]) {
-		  dv = delay_[1]->eval_const(des, path);
+		  fall_time = calculate_val(des, scope, delay_[1]);
-		  assert(dv);
-		  fall_time = dv->as_ulong();
-		  delete dv;
 
 		  if (delay_[2]) {
-			dv = delay_[2]->eval_const(des, path);
+			decay_time = calculate_val(des, scope, delay_[2]);
-			assert(dv);
+
-			decay_time = dv->as_ulong();
-			delete dv;
 		  } else {
 			if (rise_time < fall_time)
 			      decay_time = rise_time;
@@ -96,6 +115,12 @@ void PDelays::eval_delays(Design*des, const string&path,
 
 /*
  * $Log: PDelays.cc,v $
+ * Revision 1.3  2001/01/14 23:04:55  steve
+ *  Generalize the evaluation of floating point delays, and
+ *  get it working with delay assignment statements.
+ *
+ *  Allow parameters to be referenced by hierarchical name.
+ *
  * Revision 1.2  2000/02/23 02:56:53  steve
  *  Macintosh compilers do not support ident.
  *

PExpr.cc

@@ -17,7 +17,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #if !defined(WINNT) && !defined(macintosh)
-#ident "$Id: PExpr.cc,v 1.22 2001/01/12 04:31:27 steve Exp $"
+#ident "$Id: PExpr.cc,v 1.23 2001/01/14 23:04:55 steve Exp $"
 #endif
 
 # include  "PExpr.h"
@@ -133,6 +133,11 @@ const verireal& PEFNumber::value() const
       return *value_;
 }
 
+bool PEFNumber::is_constant(Module*) const
+{
+      return true;
+}
+
 PEIdent::PEIdent(const string&s)
 : text_(s), msb_(0), lsb_(0), idx_(0)
 {
@@ -246,6 +251,12 @@ bool PEUnary::is_constant(Module*m) const
 
 /*
  * $Log: PExpr.cc,v $
+ * Revision 1.23  2001/01/14 23:04:55  steve
+ *  Generalize the evaluation of floating point delays, and
+ *  get it working with delay assignment statements.
+ *
+ *  Allow parameters to be referenced by hierarchical name.
+ *
  * Revision 1.22  2001/01/12 04:31:27  steve
  *  Handle error idents in constants not in any scope (PR#97)
  *

PExpr.h

@@ -19,7 +19,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #if !defined(WINNT) && !defined(macintosh)
-#ident "$Id: PExpr.h,v 1.47 2000/12/16 19:03:30 steve Exp $"
+#ident "$Id: PExpr.h,v 1.48 2001/01/14 23:04:55 steve Exp $"
 #endif
 
 # include  <string>
@@ -88,6 +88,11 @@ class PExpr : public LineInfo {
 	// evaluated, return 0.
       virtual verinum* eval_const(const Design*des, const string&path) const;
 
+	// This attempts to evaluate a constant expression as a
+	// decimal floating point. This is used when calculating delay
+	// constants.
+      virtual verireal* eval_rconst(const Design*, const NetScope*) const;
+
 	// This method returns true if that expression is the same as
 	// this expression. This method is used for comparing
 	// expressions that must be structurally "identical".
@@ -179,6 +184,15 @@ class PEFNumber : public PExpr {
 	   any rounding that is needed to get the value. */
       virtual verinum* eval_const(const Design*des, const string&path) const;
 
+	/* This method returns the full floating point value. */
+      virtual verireal* eval_rconst(const Design*, const NetScope*) const;
+
+	/* A PEFNumber is a constant, so this returns true. */
+      virtual bool is_constant(Module*) const;
+
+      virtual NetExpr*elaborate_expr(Design*des, NetScope*) const;
+      virtual NetExpr*elaborate_pexpr(Design*des, NetScope*sc) const;
+
       virtual void dump(ostream&) const;
 
     private:
@@ -432,6 +446,12 @@ class PECallFunction : public PExpr {
 
 /*
  * $Log: PExpr.h,v $
+ * Revision 1.48  2001/01/14 23:04:55  steve
+ *  Generalize the evaluation of floating point delays, and
+ *  get it working with delay assignment statements.
+ *
+ *  Allow parameters to be referenced by hierarchical name.
+ *
  * Revision 1.47  2000/12/16 19:03:30  steve
  *  Evaluate <= and ?: in parameter expressions (PR#81)
  *

elab_expr.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_expr.cc,v 1.33 2001/01/13 22:20:08 steve Exp $"
+#ident "$Id: elab_expr.cc,v 1.34 2001/01/14 23:04:55 steve Exp $"
 #endif
 
 
@@ -269,6 +269,12 @@ NetExpr* PEConcat::elaborate_expr(Design*des, NetScope*scope) const
       return tmp;
 }
 
+NetExpr* PEFNumber::elaborate_expr(Design*des, NetScope*scope) const
+{
+      long val = value_->as_long();
+      return new NetEConst(verinum(val));
+}
+
 NetExpr* PEIdent::elaborate_expr(Design*des, NetScope*scope) const
 {
       assert(text_[0] != '$');
@@ -539,6 +545,12 @@ NetEUnary* PEUnary::elaborate_expr(Design*des, NetScope*scope) const
 
 /*
  * $Log: elab_expr.cc,v $
+ * Revision 1.34  2001/01/14 23:04:55  steve
+ *  Generalize the evaluation of floating point delays, and
+ *  get it working with delay assignment statements.
+ *
+ *  Allow parameters to be referenced by hierarchical name.
+ *
  * Revision 1.33  2001/01/13 22:20:08  steve
  *  Parse parameters within nested scopes.
  *

elab_pexpr.cc

@@ -17,10 +17,11 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #if !defined(WINNT) && !defined(macintosh)
-#ident "$Id: elab_pexpr.cc,v 1.7 2001/01/02 04:21:13 steve Exp $"
+#ident "$Id: elab_pexpr.cc,v 1.8 2001/01/14 23:04:56 steve Exp $"
 #endif
 
 # include  "PExpr.h"
+# include  "util.h"
 
 NetExpr*PExpr::elaborate_pexpr(Design*des, NetScope*sc) const
 {
@@ -103,6 +104,11 @@ NetEConcat* PEConcat::elaborate_pexpr(Design*des, NetScope*scope) const
       return tmp;
 }
 
+NetExpr*PEFNumber::elaborate_pexpr(Design*des, NetScope*scope) const
+{
+      return elaborate_expr(des, scope);
+}
+
 /*
  * Parameter expressions may reference other parameters, but only in
  * the current scope. Preserve the parameter reference in the
@@ -111,7 +117,16 @@ NetEConcat* PEConcat::elaborate_pexpr(Design*des, NetScope*scope) const
  */
 NetExpr*PEIdent::elaborate_pexpr(Design*des, NetScope*scope) const
 {
-      const NetExpr*ex = scope->get_parameter(text_);
+      string path = text_;
+      string name = parse_last_name(path);
+
+      NetScope*pscope = scope;
+      if (path != "")
+	    pscope = des->find_scope(scope, path);
+
+      assert(pscope);
+
+      const NetExpr*ex = pscope->get_parameter(name);
       if (ex == 0) {
 	    cerr << get_line() << ": error: identifier ``" << text_ <<
 		  "'' is not a parameter in " << scope->name() << "." << endl;
@@ -119,7 +134,7 @@ NetExpr*PEIdent::elaborate_pexpr(Design*des, NetScope*scope) const
 	    return 0;
       }
 
-      NetExpr*res = new NetEParam(des, scope, text_);
+      NetExpr*res = new NetEParam(des, pscope, name);
       assert(res);
       return res;
 }
@@ -184,6 +199,12 @@ NetExpr*PEUnary::elaborate_pexpr (Design*des, NetScope*scope) const
 
 /*
  * $Log: elab_pexpr.cc,v $
+ * Revision 1.8  2001/01/14 23:04:56  steve
+ *  Generalize the evaluation of floating point delays, and
+ *  get it working with delay assignment statements.
+ *
+ *  Allow parameters to be referenced by hierarchical name.
+ *
  * Revision 1.7  2001/01/02 04:21:13  steve
  *  Support a bunch of unary operators in parameter expressions.
  *

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 1.204 2001/01/10 03:13:23 steve Exp $"
+#ident "$Id: elaborate.cc,v 1.205 2001/01/14 23:04:56 steve Exp $"
 #endif
 
 /*
@@ -1538,20 +1538,23 @@ NetProc* PDelayStatement::elaborate(Design*des, const string&path) const
 	   floating point number. In this case, we need to scale the
 	   delay to the units of the design. */
 
-      if (const PEFNumber*fn = dynamic_cast<const PEFNumber*>(delay_)) {
+      if (verireal*fn = delay_? delay_->eval_rconst(des, scope) : 0) {
 	    int shift = scope->time_unit() - des->get_precision();
 
-	    long delay = fn->value().as_long(shift);
+	    long delay = fn->as_long(shift);
 	    if (delay < 0)
 		  delay = 0;
 
+	    delete fn;
+
 	    if (statement_)
-		  return new NetPDelay(delay, statement_->elaborate(des, path));
+		return new NetPDelay(delay, statement_->elaborate(des, path));
 	    else
-		  return new NetPDelay(delay, 0);
+		return new NetPDelay(delay, 0);
 
       }
 
+
       verinum*num = delay_->eval_const(des, path);
       if (num == 0) {
 	      /* Ah, the delay is not constant. OK, elaborate the
@@ -1567,6 +1570,7 @@ NetProc* PDelayStatement::elaborate(Design*des, const string&path) const
 	/* Convert the delay in the units of the scope to the
 	   precision of the design as a whole. */
       unsigned long val = des->scale_to_precision(num->as_ulong(), scope);
+      delete num;
 
 	/* If there is a statement, then elaborate it and create a
 	   NetPDelay statement to contain it. Note that we create a
@@ -2351,6 +2355,12 @@ Design* elaborate(const map<string,Module*>&modules,
 
 /*
  * $Log: elaborate.cc,v $
+ * Revision 1.205  2001/01/14 23:04:56  steve
+ *  Generalize the evaluation of floating point delays, and
+ *  get it working with delay assignment statements.
+ *
+ *  Allow parameters to be referenced by hierarchical name.
+ *
  * Revision 1.204  2001/01/10 03:13:23  steve
  *  Build task outputs as lval instead of nets. (PR#98)
  *

eval.cc

@@ -17,11 +17,12 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #if !defined(WINNT) && !defined(macintosh)
-#ident "$Id: eval.cc,v 1.17 2001/01/04 04:47:51 steve Exp $"
+#ident "$Id: eval.cc,v 1.18 2001/01/14 23:04:56 steve Exp $"
 #endif
 
 # include  "PExpr.h"
 # include  "netlist.h"
+# include  "compiler.h"
 
 verinum* PExpr::eval_const(const Design*, const string&) const
 {
@@ -104,6 +105,7 @@ verinum* PEBinary::eval_const(const Design*des, const string&path) const
       return res;
 }
 
+
 /*
  * Evaluate an identifier as a constant expression. This is only
  * possible if the identifier is that of a parameter.
@@ -183,6 +185,12 @@ verinum* PEUnary::eval_const(const Design*des, const string&path) const
 
 /*
  * $Log: eval.cc,v $
+ * Revision 1.18  2001/01/14 23:04:56  steve
+ *  Generalize the evaluation of floating point delays, and
+ *  get it working with delay assignment statements.
+ *
+ *  Allow parameters to be referenced by hierarchical name.
+ *
  * Revision 1.17  2001/01/04 04:47:51  steve
  *  Add support for << is signal indices.
  *

eval_rconst.cc

@@ -0,0 +1,46 @@
+/*
+ * Copyright (c) 2001 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: eval_rconst.cc,v 1.1 2001/01/14 23:04:56 steve Exp $"
+#endif
+
+# include  "PExpr.h"
+
+verireal* PExpr::eval_rconst(const Design*, const NetScope*) const
+{
+      return 0;
+}
+
+verireal* PEFNumber::eval_rconst(const Design*, const NetScope*) const
+{
+      verireal*res = new verireal;
+      *res = *value_;
+      return res;
+}
+
+/*
+ * $Log: eval_rconst.cc,v $
+ * Revision 1.1  2001/01/14 23:04:56  steve
+ *  Generalize the evaluation of floating point delays, and
+ *  get it working with delay assignment statements.
+ *
+ *  Allow parameters to be referenced by hierarchical name.
+ *
+ */
+

eval_tree.cc

@@ -17,7 +17,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #if !defined(WINNT) && !defined(macintosh)
-#ident "$Id: eval_tree.cc,v 1.20 2001/01/04 16:49:50 steve Exp $"
+#ident "$Id: eval_tree.cc,v 1.21 2001/01/14 23:04:56 steve Exp $"
 #endif
 
 # include  "netlist.h"
@@ -574,6 +574,13 @@ NetExpr* NetEParam::eval_tree()
 
       assert(scope_);
       const NetExpr*expr = scope_->get_parameter(name_);
+      if (expr == 0) {
+	    cerr << get_line() << ": internal error: Unable to match "
+		 << "parameter " << name_ << " in scope "
+		 << scope_->name() << endl;
+	    return 0;
+      }
+
       assert(expr);
 
       NetExpr*nexpr = expr->dup_expr();
@@ -815,6 +822,12 @@ NetEConst* NetEUReduce::eval_tree()
 
 /*
  * $Log: eval_tree.cc,v $
+ * Revision 1.21  2001/01/14 23:04:56  steve
+ *  Generalize the evaluation of floating point delays, and
+ *  get it working with delay assignment statements.
+ *
+ *  Allow parameters to be referenced by hierarchical name.
+ *
  * Revision 1.20  2001/01/04 16:49:50  steve
  *  Evaluate constant === and !== expressions.
  *

net_design.cc

@@ -17,7 +17,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #if !defined(WINNT) && !defined(macintosh)
-#ident "$Id: net_design.cc,v 1.17 2000/12/16 01:45:48 steve Exp $"
+#ident "$Id: net_design.cc,v 1.18 2001/01/14 23:04:56 steve Exp $"
 #endif
 
 /*
@@ -29,20 +29,6 @@
 # include  "util.h"
 # include  <strstream>
 
-static string parse_last_name(string&path)
-{
-      unsigned pos = path.rfind('.');
-      if (pos > path.length()) {
-	    string res = path;
-	    path = "";
-	    return res;
-      }
-
-      string res = path.substr(pos+1, path.length());
-      path = path.substr(0, pos);
-      return res;
-}
-
 Design:: Design()
 : errors(0), root_scope_(0), nodes_(0), procs_(0), lcounter_(0)
 {
@@ -487,6 +473,12 @@ void Design::delete_process(NetProcTop*top)
 
 /*
  * $Log: net_design.cc,v $
+ * Revision 1.18  2001/01/14 23:04:56  steve
+ *  Generalize the evaluation of floating point delays, and
+ *  get it working with delay assignment statements.
+ *
+ *  Allow parameters to be referenced by hierarchical name.
+ *
  * Revision 1.17  2000/12/16 01:45:48  steve
  *  Detect recursive instantiations (PR#2)
  *

parse.y

@@ -19,7 +19,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #if !defined(WINNT) && !defined(macintosh)
-#ident "$Id: parse.y,v 1.117 2001/01/13 22:20:08 steve Exp $"
+#ident "$Id: parse.y,v 1.118 2001/01/14 23:04:56 steve Exp $"
 #endif
 
 # include  "parse_misc.h"
@@ -793,9 +793,10 @@ expr_primary
 		  $$ = tmp;
 		}
 	| REALTIME
-		{ yyerror(@1, "sorry: real constants not supported.");
+		{ PEFNumber*tmp = new PEFNumber($1);
-		  delete $1;
+		  tmp->set_file(@1.text);
-		  $$ = 0;
+		  tmp->set_lineno(@1.first_line);
+		  $$ = tmp;
 		}
 	| STRING
 		{ PEString*tmp = new PEString($1);

pform.cc

@@ -17,7 +17,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #if !defined(WINNT) && !defined(macintosh)
-#ident "$Id: pform.cc,v 1.71 2001/01/10 05:32:44 steve Exp $"
+#ident "$Id: pform.cc,v 1.72 2001/01/14 23:04:56 steve Exp $"
 #endif
 
 # include  "compiler.h"
@@ -525,6 +525,7 @@ void pform_make_modgates(const string&type,
 			 struct parmvalue_t*overrides,
 			 svector<lgate>*gates)
 {
+#if 0
       if (overrides && overrides->by_order)
 	    for (unsigned idx = 0 ;  idx < overrides->by_order->count() ;  idx += 1)
 		  if (! pform_expression_is_constant((*overrides->by_order)[idx])) {
@@ -532,7 +533,7 @@ void pform_make_modgates(const string&type,
 				" must be constant.");
 			return;
 		  }
-
+#endif
       for (unsigned idx = 0 ;  idx < gates->count() ;  idx += 1) {
 	    lgate cur = (*gates)[idx];
 
@@ -1010,6 +1011,12 @@ int pform_parse(const char*path, map<string,Module*>&modules,
 
 /*
  * $Log: pform.cc,v $
+ * Revision 1.72  2001/01/14 23:04:56  steve
+ *  Generalize the evaluation of floating point delays, and
+ *  get it working with delay assignment statements.
+ *
+ *  Allow parameters to be referenced by hierarchical name.
+ *
  * Revision 1.71  2001/01/10 05:32:44  steve
  *  Match memories within task scopes. (PR#101)
  *

util.cc

@@ -17,7 +17,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #if !defined(WINNT) && !defined(macintosh)
-#ident "$Id: util.cc,v 1.1 2000/04/28 16:50:53 steve Exp $"
+#ident "$Id: util.cc,v 1.2 2001/01/14 23:04:56 steve Exp $"
 #endif
 
 # include  "util.h"
@@ -36,8 +36,28 @@ string parse_first_name(string&path)
       return res;
 }
 
+string parse_last_name(string&path)
+{
+      unsigned pos = path.rfind('.');
+      if (pos > path.length()) {
+	    string res = path;
+	    path = "";
+	    return res;
+      }
+
+      string res = path.substr(pos+1, path.length());
+      path = path.substr(0, pos);
+      return res;
+}
+
 /*
  * $Log: util.cc,v $
+ * Revision 1.2  2001/01/14 23:04:56  steve
+ *  Generalize the evaluation of floating point delays, and
+ *  get it working with delay assignment statements.
+ *
+ *  Allow parameters to be referenced by hierarchical name.
+ *
  * Revision 1.1  2000/04/28 16:50:53  steve
  *  Catch memory word parameters to tasks.
  *

util.h

@@ -19,7 +19,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #if !defined(WINNT) && !defined(macintosh)
-#ident "$Id: util.h,v 1.1 2000/04/29 04:53:44 steve Exp $"
+#ident "$Id: util.h,v 1.2 2001/01/14 23:04:56 steve Exp $"
 #endif
 
 # include  <string>
@@ -31,8 +31,16 @@
  */
 extern string parse_first_name(string&path);
 
+extern string parse_last_name(string&path);
+
 /*
  * $Log: util.h,v $
+ * Revision 1.2  2001/01/14 23:04:56  steve
+ *  Generalize the evaluation of floating point delays, and
+ *  get it working with delay assignment statements.
+ *
+ *  Allow parameters to be referenced by hierarchical name.
+ *
  * Revision 1.1  2000/04/29 04:53:44  steve
  *  missing header file.
  *