diff --git a/vhdlpp/entity_elaborate.cc b/vhdlpp/entity_elaborate.cc
index 861029ca7..4d74d0039 100644
--- a/vhdlpp/entity_elaborate.cc
+++ b/vhdlpp/entity_elaborate.cc
@@ -92,7 +92,8 @@ int Entity::elaborate_generic_exprs_()
       for (vector<InterfacePort*>::const_iterator cur = parms_.begin()
 		 ; cur != parms_.end() ; ++cur) {
 	    InterfacePort*curp = *cur;
-	    curp->expr->elaborate_expr(this, 0, curp->type);
+	    if(curp->expr)
+		curp->expr->elaborate_expr(this, 0, curp->type);
       }
       return errors;
 }
diff --git a/vhdlpp/entity_emit.cc b/vhdlpp/entity_emit.cc
index 41fb1eef8..268b36f7d 100644
--- a/vhdlpp/entity_emit.cc
+++ b/vhdlpp/entity_emit.cc
@@ -50,9 +50,11 @@ int Entity::emit(ostream&out)
 		  const InterfacePort*curp = *cur;
 		  if (cur != parms_.begin())
 			out << ", ";
-		  out << "parameter \\" << curp->name << " = ";
-		  ivl_assert(*this, curp->expr);
-		  errors += curp->expr->emit(out, this, 0);
+		  out << "parameter \\" << curp->name << " ";
+		  if(curp->expr) {
+			out << "= ";
+			errors += curp->expr->emit(out, this, 0);
+                  }
 	    }
 	    out << ") ";
       }