From 6d0edcf58af6804d967e3ed6b94f338e3e464e94 Mon Sep 17 00:00:00 2001
From: steve <steve>
Date: Thu, 30 Dec 1999 19:06:14 +0000
Subject: [PATCH]  Support reg initial assignment syntax.

---
 parse.y  |  8 +++++---
 pform.cc | 47 +++++++++++++++++++++++++++++++++++++++++++++--
 pform.h  |  7 ++++++-
 3 files changed, 56 insertions(+), 6 deletions(-)

diff --git a/parse.y b/parse.y
index 0bc08b90a..d47d933b0 100644
--- a/parse.y
+++ b/parse.y
@@ -19,7 +19,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #if !defined(WINNT)
-#ident "$Id: parse.y,v 1.76 1999/11/15 04:43:52 steve Exp $"
+#ident "$Id: parse.y,v 1.77 1999/12/30 19:06:14 steve Exp $"
 #endif
 
 # include  "parse_misc.h"
@@ -1390,8 +1390,10 @@ register_variable
 		}
 	| IDENTIFIER '=' expression
 		{ pform_makewire(@1, $1, NetNet::REG);
-		  yyerror(@2, "error: net declaration assignment to reg/integer not allowed.");
-		  delete $3;
+		  if (! pform_expression_is_constant($3))
+			yyerror(@3, "error: register declaration assignment"
+				" value must be a constant expression.");
+		  pform_make_reginit(@1, $1, $3);
 		  $$ = $1;
 		}
 	| IDENTIFIER '[' expression ':' expression ']'
diff --git a/pform.cc b/pform.cc
index dbaeb9735..9a8b021b3 100644
--- a/pform.cc
+++ b/pform.cc
@@ -17,7 +17,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #if !defined(WINNT)
-#ident "$Id: pform.cc,v 1.48 1999/12/11 05:45:41 steve Exp $"
+#ident "$Id: pform.cc,v 1.49 1999/12/30 19:06:14 steve Exp $"
 #endif
 
 # include  "compiler.h"
@@ -407,6 +407,46 @@ void pform_make_pgassign_list(svector<PExpr*>*alist,
 	}
 }
 
+/*
+ * this function makes the initial assignment to a register as given
+ * in the source. It handles the case where a reg variable is assigned
+ * where it it declared:
+ *
+ *    reg foo = <expr>;
+ *
+ * This is equivilent to the combination of statements:
+ *
+ *    reg foo;
+ *    initital foo = <expr>;
+ *
+ * and that is how it is parsed. This syntax is not part of the
+ * IEEE1364-1994 standard, but is approved by OVI as enhancement
+ * BTF-B14.
+ */
+void pform_make_reginit(const struct vlltype&li,
+			const string&name, PExpr*expr)
+{
+      const string sname = scoped_name(name);
+      PWire*cur = pform_cur_module->get_wire(sname);
+      if (cur == 0) {
+	    VLerror(li, "internal error: reginit to non-register?");
+	    delete expr;
+	    return;
+      }
+
+      PEIdent*lval = new PEIdent(sname);
+      lval->set_file(li.text);
+      lval->set_lineno(li.first_line);
+      PAssign*ass = new PAssign(lval, expr);
+      ass->set_file(li.text);
+      ass->set_lineno(li.first_line);
+      PProcess*top = new PProcess(PProcess::PR_INITIAL, ass);
+      top->set_file(li.text);
+      top->set_lineno(li.first_line);
+
+      pform_cur_module->add_behavior(top);
+}
+
 void pform_makewire(const vlltype&li, const string&nm,
 		    NetNet::Type type)
 {
@@ -416,7 +456,7 @@ void pform_makewire(const vlltype&li, const string&nm,
 	    if (cur->get_wire_type() != NetNet::IMPLICIT) {
 		  strstream msg;
 		  msg << name << " previously defined at " <<
-			cur->get_line() << ".";
+			cur->get_line() << "." << ends;
 		  VLerror(msg.str());
 	    } else {
 		  bool rc = cur->set_wire_type(type);
@@ -725,6 +765,9 @@ int pform_parse(const char*path, map<string,Module*>&modules,
 
 /*
  * $Log: pform.cc,v $
+ * Revision 1.49  1999/12/30 19:06:14  steve
+ *  Support reg initial assignment syntax.
+ *
  * Revision 1.48  1999/12/11 05:45:41  steve
  *  Fix support for attaching attributes to primitive gates.
  *
diff --git a/pform.h b/pform.h
index 82db4ab65..f9943b723 100644
--- a/pform.h
+++ b/pform.h
@@ -19,7 +19,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #if !defined(WINNT)
-#ident "$Id: pform.h,v 1.31 1999/09/10 05:02:09 steve Exp $"
+#ident "$Id: pform.h,v 1.32 1999/12/30 19:06:14 steve Exp $"
 #endif
 
 # include  "netlist.h"
@@ -116,6 +116,8 @@ extern void pform_makewire(const struct vlltype&li, const string&name,
 			   NetNet::Type type = NetNet::IMPLICIT);
 extern void pform_makewire(const struct vlltype&li, const list<string>*names,
 			   NetNet::Type type);
+extern void pform_make_reginit(const struct vlltype&li,
+			       const string&name, PExpr*expr);
 extern void pform_set_port_type(list<string>*names, NetNet::PortType);
 extern void pform_set_net_range(list<string>*names, const svector<PExpr*>*);
 extern void pform_set_reg_idx(const string&name, PExpr*l, PExpr*r);
@@ -174,6 +176,9 @@ extern void pform_dump(ostream&out, Module*mod);
 
 /*
  * $Log: pform.h,v $
+ * Revision 1.32  1999/12/30 19:06:14  steve
+ *  Support reg initial assignment syntax.
+ *
  * Revision 1.31  1999/09/10 05:02:09  steve
  *  Handle integers at task parameters.
  *