diff --git a/rocket/src/main/scala/util.scala b/rocket/src/main/scala/util.scala
index e08791ef..e52b2e4d 100644
--- a/rocket/src/main/scala/util.scala
+++ b/rocket/src/main/scala/util.scala
@@ -6,10 +6,10 @@ import scala.math._
 
 class Unsigned(x: Int) {
   require(x >= 0)
-  def size: Int = { require(x > 0); ceil(log(x)/log(2)).toInt }
+  def clog2: Int = { require(x > 0); ceil(log(x)/log(2)).toInt }
   def log2: Int = { require(x > 0); floor(log(x)/log(2)).toInt }
   def isPow2: Boolean = x > 0 && (x & (x-1)) == 0
-  def nextPow2: Int = if (x == 0) 1 else 1 << size
+  def nextPow2: Int = if (x == 0) 1 else 1 << clog2
 }
 
 object Util {