diff --git a/sim/host.hh b/sim/host.hh
index ef70080..f7e64f2 100644
--- a/sim/host.hh
+++ b/sim/host.hh
@@ -54,4 +54,12 @@
  */
 typedef int64_t Tick;
 
+/**
+ * Address type
+ * This will probably be moved somewhere else in the near future.
+ * This should be at least as big as the biggest address width in use
+ * in the system, which will probably be 64 bits.
+ */
+typedef uint64_t Addr;
+
 #endif // __HOST_H__