diff -r 5447274f0321 -r 790cc8784820 rt/vm/src/main/java/org/apidesign/vm4brwsr/NumberOperations.java
--- a/rt/vm/src/main/java/org/apidesign/vm4brwsr/NumberOperations.java	Wed Jan 27 06:46:03 2016 +0100
+++ b/rt/vm/src/main/java/org/apidesign/vm4brwsr/NumberOperations.java	Wed Jan 27 21:17:44 2016 +0100
@@ -157,7 +157,7 @@
                 "    var __and64 = Number.prototype['__bit64']['and64'];\n" +
                 "    var __or64 = Number.prototype['__bit64']['or64'];\n" +
                 "    var __xor64 = Number.prototype['__bit64']['xor64'];\n" +
-                "    var __neg64 = function(x) { return x.neg64(); };\n" +
+                "    var __neg64 = Number.prototype['__bit64']['neg64'];\n" +
                 "    var __shl64 = Number.prototype['__bit64']['shl64'];\n" +
                 "    var __shr64 = Number.prototype['__bit64']['shr64'];\n" +
                 "    var __ushr64 = Number.prototype['__bit64']['ushr64'];\n" +