diff -r 42c6e5a05360 -r 71e5cd5b29bc rt/vm/src/main/java/org/apidesign/vm4brwsr/VM.java
--- a/rt/vm/src/main/java/org/apidesign/vm4brwsr/VM.java	Sat Dec 26 08:59:42 2015 +0100
+++ b/rt/vm/src/main/java/org/apidesign/vm4brwsr/VM.java	Sun Jan 24 14:31:36 2016 +0100
@@ -459,7 +459,15 @@
 
         @Override
         protected void generatePrologue() throws IOException {
-            append("(function VM(global) {var fillInVMSkeleton = function(vm) {");
+            append("(function VM(global) {var myNum = {};\n"
+                + "    myNum.mod32 = function(a, x) {\n"
+                + "        if (x === 0) {\n"
+                + "            __handleDivByZero();\n"
+                + "        }\n"
+                + "        return a % x;\n"
+                + "    }\n"
+                + ""
+                + "var fillInVMSkeleton = function(vm) {");
         }
 
         @Override
@@ -731,6 +739,14 @@
             }
             append(
                   "\n}, function(exports) {\n"
+                + "  var myNum = {};\n"
+                      + "    myNum.mod32 = function(a, x) {\n"
+                + "        if (x === 0) {\n"
+                + "            __handleDivByZero();\n"
+                + "        }\n"
+                + "        return a % x;\n"
+                + "    }\n"
+                + ""
                 + "  var vm = {};\n");
             append("  function link(n, assign) {\n"
                 + "    return function() {\n"