--- a/sandbox/jlf/trunk/interpreter/platform/windows/SysActivity.cpp
+++ b/sandbox/jlf/trunk/interpreter/platform/windows/SysActivity.cpp
@@ -131,3 +131,18 @@
     size_t temp;
     return(char *)&temp - stackSize;
 }
+
+
+wholenumber_t yieldCount = 0; // Monitoring
+
+void SysActivity::yield()
+{
+    yieldCount += 1;
+    // just give up the time slice
+    Sleep(0);
+}
+
+wholenumber_t SysActivity::yieldCounter()
+{
+    return yieldCount;
+}