Index: lucene/src/java/org/apache/lucene/search/Similarity.java
===================================================================
--- lucene/src/java/org/apache/lucene/search/Similarity.java	(revision 1072589)
+++ lucene/src/java/org/apache/lucene/search/Similarity.java	(working copy)
@@ -532,7 +532,8 @@
   private static final float[] NORM_TABLE = new float[256];
 
   static {
-    for (int i = 0; i < 256; i++)
+    NORM_TABLE[0] = 4.656613E-10f;
+    for (int i = 1; i < 256; i++)
       NORM_TABLE[i] = SmallFloat.byte315ToFloat((byte)i);
   }