From 2229ad896b72b309de6c417f11c9dad9c8efd2d8 Mon Sep 17 00:00:00 2001
From: Stephen Williams <steve@icarus.com>
Date: Wed, 7 Oct 2009 12:58:19 -0700
Subject: [PATCH] tranif control ports handle nil inputs

In certain special cases, it is possible for the tranif control input
to be nil. (probably only during startup.) Treat that case as HiZ.
---
 vvp/island_tran.cc | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/vvp/island_tran.cc b/vvp/island_tran.cc
index 91e2d7f04..bb7e1747b 100644
--- a/vvp/island_tran.cc
+++ b/vvp/island_tran.cc
@@ -114,7 +114,11 @@ bool vvp_island_branch_tran::run_test_enabled()
       }
 
       enabled_flag = false;
-      vvp_bit4_t enable_val = ep->invalue.value(0).value();
+      vvp_bit4_t enable_val;
+      if (ep->invalue.size() == 0)
+	    enable_val = BIT4_Z;
+      else
+	    enable_val = ep->invalue.value(0).value();
 
       if (active_high==true && enable_val != BIT4_1)
 	    return false;