diff --git a/compiler.h b/compiler.h
index d444d2617..ec62aff60 100644
--- a/compiler.h
+++ b/compiler.h
@@ -19,7 +19,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #ifdef HAVE_CVS_IDENT
-#ident "$Id: compiler.h,v 1.23 2004/09/05 17:44:41 steve Exp $"
+#ident "$Id: compiler.h,v 1.24 2004/09/10 23:51:42 steve Exp $"
 #endif
 
 # include  <list>
@@ -82,6 +82,7 @@ extern bool warn_portbinding;
 extern bool verbose_flag;
 
 extern bool debug_scopes;
+extern bool debug_eval_tree;
 
 /* Path to a directory useful for finding subcomponents. */
 extern const char*basedir;
@@ -134,6 +135,9 @@ extern int load_sys_func_table(const char*path);
 
 /*
  * $Log: compiler.h,v $
+ * Revision 1.24  2004/09/10 23:51:42  steve
+ *  Fix the evaluation of constant ternary expressions.
+ *
  * Revision 1.23  2004/09/05 17:44:41  steve
  *  Add support for module instance arrays.
  *
diff --git a/eval_tree.cc b/eval_tree.cc
index 0dcf75418..b9dc35660 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 1.60 2004/02/20 06:22:56 steve Exp $"
+#ident "$Id: eval_tree.cc,v 1.61 2004/09/10 23:51:42 steve Exp $"
 #endif
 
 # include "config.h"
@@ -1305,18 +1305,50 @@ NetExpr* NetETernary::eval_tree()
       if (c == 0)
 	    return 0;
 
+	/* Check the boolean value of the constant condition
+	   expression. Note that the X case is handled explicitly, so
+	   we must differentiate. */
+
+      verinum cond_value = c->value();
+      bool true_flag = false;
+      bool x_flag = false;
+
+      for (unsigned idx = 0 ;  idx < cond_value.len() ;  idx += 1) {
+	    switch (cond_value.get(idx)) {
+		case verinum::V1:
+		  true_flag = true;
+		  break;
+		case verinum::V0:
+		  break;
+		default:
+		  x_flag = true;
+	    }
+      }
+
 
 	/* If the condition is 1 or 0, return the true or false
 	   expression. Try to evaluate the expression down as far as
 	   we can. */
 
-      if (c->value().get(0) == verinum::V1)
+      if (true_flag) {
+	    if (debug_eval_tree) {
+		  cerr << get_line() << ": debug: Evaluate ternary with "
+		       << "constant condition value: " << c->value() << endl;
+		  cerr << get_line() << ":      : Selecting true case: "
+		       << *true_val_ << endl;
+	    }
 	    return true_val_->dup_expr();
+      }
 
-
-      if (c->value().get(0) == verinum::V0)
+      if (! x_flag) {
+	    if (debug_eval_tree) {
+		  cerr << get_line() << ": debug: Evaluate ternary with "
+		       << "constant condition value: " << c->value() << endl;
+		  cerr << get_line() << ":      : Selecting false case: "
+		       << *true_val_ << endl;
+	    }
 	    return false_val_->dup_expr();
-
+      }
 
 	/* Here we have a more complex case. We need to evaluate both
 	   expressions down to constants then compare the values to
@@ -1332,13 +1364,15 @@ NetExpr* NetETernary::eval_tree()
 	    return 0;
 
 
-      unsigned size = t->expr_width();
-      assert(size == f->expr_width());
+      unsigned tsize = t->expr_width();
+      unsigned fsize = f->expr_width();
+	/* Size of the result is the size of the widest operand. */
+      unsigned rsize = tsize > fsize? tsize : fsize;
 
-      verinum val (verinum::V0, size);
-      for (unsigned idx = 0 ;  idx < size ;  idx += 1) {
-	    verinum::V tv = t->value().get(idx);
-	    verinum::V fv = f->value().get(idx);
+      verinum val (verinum::V0, rsize);
+      for (unsigned idx = 0 ;  idx < rsize ;  idx += 1) {
+	    verinum::V tv = idx < tsize? t->value().get(idx) : verinum::V0;
+	    verinum::V fv = idx < rsize? f->value().get(idx) : verinum::V0;
 
 	    if (tv == fv)
 		  val.set(idx, tv);
@@ -1346,6 +1380,13 @@ NetExpr* NetETernary::eval_tree()
 		  val.set(idx, verinum::Vx);
       }
 
+      if (debug_eval_tree) {
+	    cerr << get_line() << ": debug: Evaluate ternary with "
+		 << "constant condition value: " << c->value() << endl;
+	    cerr << get_line() << ":      : Blending cases to get "
+		 << val << endl;
+      }
+
       NetEConst*rc = new NetEConst(val);
       rc->set_line(*this);
       return rc;
@@ -1510,6 +1551,9 @@ NetEConst* NetEUReduce::eval_tree()
 
 /*
  * $Log: eval_tree.cc,v $
+ * Revision 1.61  2004/09/10 23:51:42  steve
+ *  Fix the evaluation of constant ternary expressions.
+ *
  * Revision 1.60  2004/02/20 06:22:56  steve
  *  parameter keys are per_strings.
  *
diff --git a/main.cc b/main.cc
index 4858cf7c3..191fe115f 100644
--- a/main.cc
+++ b/main.cc
@@ -19,7 +19,7 @@ const char COPYRIGHT[] =
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #ifdef HAVE_CVS_IDENT
-#ident "$Id: main.cc,v 1.83 2004/09/05 17:44:42 steve Exp $"
+#ident "$Id: main.cc,v 1.84 2004/09/10 23:51:42 steve Exp $"
 #endif
 
 # include "config.h"
@@ -110,7 +110,7 @@ bool error_implicit = false;
  * Debug message class flags.
  */
 bool debug_scopes = false;
-
+bool debug_eval_tree = false;
 /*
  * Verbose messages enabled.
  */
@@ -307,6 +307,9 @@ static void read_iconfig_file(const char*ipath)
 		  if (strcmp(cp, "scope") == 0) {
 			debug_scopes = true;
 			cerr << "debug: Enable scope debug" << endl;
+		  } else if (strcmp(cp,"eval_tree") == 0) {
+			debug_eval_tree = true;
+			cerr << "debug: Enable eval_tree debug" << endl;
 		  } else {
 		  }
 
@@ -737,6 +740,9 @@ int main(int argc, char*argv[])
 
 /*
  * $Log: main.cc,v $
+ * Revision 1.84  2004/09/10 23:51:42  steve
+ *  Fix the evaluation of constant ternary expressions.
+ *
  * Revision 1.83  2004/09/05 17:44:42  steve
  *  Add support for module instance arrays.
  *