From 9f80ed32b690f61ec197aa7357676aefd8ec4029 Mon Sep 17 00:00:00 2001
From: steve <steve>
Date: Thu, 5 Dec 2002 02:14:33 +0000
Subject: [PATCH]  Support bit select in constant expressions.

---
 elab_pexpr.cc | 28 ++++++++++++++++++++-------
 eval_tree.cc  | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++-
 netlist.h     |  6 +++++-
 3 files changed, 77 insertions(+), 9 deletions(-)

diff --git a/elab_pexpr.cc b/elab_pexpr.cc
index 9e95f79e8..e38bfb7bf 100644
--- a/elab_pexpr.cc
+++ b/elab_pexpr.cc
@@ -17,7 +17,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #ifdef HAVE_CVS_IDENT
-#ident "$Id: elab_pexpr.cc,v 1.17 2002/11/09 01:40:19 steve Exp $"
+#ident "$Id: elab_pexpr.cc,v 1.18 2002/12/05 02:14:33 steve Exp $"
 #endif
 
 # include "config.h"
@@ -145,15 +145,26 @@ NetExpr*PEIdent::elaborate_pexpr(Design*des, NetScope*scope) const
 	    return 0;
       }
 
-      if (msb_ || lsb_ || idx_) {
-	    cerr << get_line() << ": error: Cannot bit/part select "
-		  "bits of parameters." << endl;
-	    des->errors += 1;
-      }
-
       NetExpr*res = new NetEParam(des, pscope, hname_t(name));
       assert(res);
       delete name;
+
+      assert(idx_ == 0);
+      if (msb_ && lsb_) {
+	    cerr << get_line() << ": sorry: Cannot part select "
+		  "bits of parameters." << endl;
+	    des->errors += 1;
+
+      } else if (msb_) {
+
+	      /* We have here a bit select. Insert a NetESelect node
+		 to handle it. */
+	    NetExpr*tmp = msb_->elaborate_pexpr(des, scope);
+	    if (tmp != 0) {
+		  res = new NetESelect(res, tmp, 1);
+	    }
+      }
+
       return res;
 }
 
@@ -217,6 +228,9 @@ NetExpr*PEUnary::elaborate_pexpr (Design*des, NetScope*scope) const
 
 /*
  * $Log: elab_pexpr.cc,v $
+ * Revision 1.18  2002/12/05 02:14:33  steve
+ *  Support bit select in constant expressions.
+ *
  * Revision 1.17  2002/11/09 01:40:19  steve
  *  Postpone parameter width check to evaluation.
  *
diff --git a/eval_tree.cc b/eval_tree.cc
index c1c7afa27..4ca99989f 100644
--- a/eval_tree.cc
+++ b/eval_tree.cc
@@ -17,7 +17,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #ifdef HAVE_CVS_IDENT
-#ident "$Id: eval_tree.cc,v 1.43 2002/11/09 01:40:19 steve Exp $"
+#ident "$Id: eval_tree.cc,v 1.44 2002/12/05 02:14:33 steve Exp $"
 #endif
 
 # include "config.h"
@@ -894,6 +894,53 @@ NetExpr* NetEParam::eval_tree()
       return res->dup_expr();
 }
 
+NetEConst* NetESelect::eval_tree()
+{
+      NetEConst*expr = dynamic_cast<NetEConst*>(expr_);
+      if (expr == 0) {
+	    NetExpr*tmp = expr_->eval_tree();
+	    if (tmp != 0) {
+		  delete expr_;
+		  expr_ = tmp;
+	    }
+
+	    expr = dynamic_cast<NetEConst*>(expr_);
+      }
+
+      NetEConst*base = dynamic_cast<NetEConst*>(base_);
+      if (base == 0) {
+	    NetExpr*tmp = base_->eval_tree();
+	    if (tmp != 0) {
+		  delete base_;
+		  base_ = tmp;
+	    }
+
+	    base = dynamic_cast<NetEConst*>(base_);
+      }
+
+      if (expr == 0)
+	    return 0;
+      if (base == 0)
+	    return 0;
+
+      verinum eval = expr->value();
+      verinum oval (verinum::V0, expr_width(), true);
+      long bval = base->value().as_long();
+
+      for (long idx = 0 ;  idx < expr_width() ;  idx += 1) {
+	    if ((bval >= eval.len()) || (bval < 0))
+		  oval.set(idx, verinum::Vx);
+	    else 
+		  oval.set(idx, eval.get(bval));
+
+	    bval += 1;
+      }
+
+      NetEConst*res = new NetEConst(oval);
+      return res;
+}
+
+
 /*
  * A ternary expression evaluation is controlled by the condition
  * expression. If the condition evaluates to true or false, then
@@ -1140,6 +1187,9 @@ NetEConst* NetEUReduce::eval_tree()
 
 /*
  * $Log: eval_tree.cc,v $
+ * Revision 1.44  2002/12/05 02:14:33  steve
+ *  Support bit select in constant expressions.
+ *
  * Revision 1.43  2002/11/09 01:40:19  steve
  *  Postpone parameter width check to evaluation.
  *
diff --git a/netlist.h b/netlist.h
index 62bcbf9d3..be9123eef 100644
--- a/netlist.h
+++ b/netlist.h
@@ -19,7 +19,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #ifdef HAVE_CVS_IDENT
-#ident "$Id: netlist.h,v 1.269 2002/11/09 01:40:19 steve Exp $"
+#ident "$Id: netlist.h,v 1.270 2002/12/05 02:14:33 steve Exp $"
 #endif
 
 /*
@@ -2494,6 +2494,7 @@ class NetESelect  : public NetExpr {
       virtual bool set_width(unsigned w);
       virtual bool has_width() const;
       virtual void expr_scan(struct expr_scan_t*) const;
+      virtual NetEConst* eval_tree();
       virtual NetESelect* dup_expr() const;
 
     private:
@@ -3084,6 +3085,9 @@ extern ostream& operator << (ostream&, NetNet::Type);
 
 /*
  * $Log: netlist.h,v $
+ * Revision 1.270  2002/12/05 02:14:33  steve
+ *  Support bit select in constant expressions.
+ *
  * Revision 1.269  2002/11/09 01:40:19  steve
  *  Postpone parameter width check to evaluation.
  *