Abstract: An extended mode analyzer (EMA) processes source code modules, detects suspicious instruction patterns and produces recommendations for code modification. The EMA applies knowledge based technology to the problem of massive source code conversion. The knowledge base component within the EMA models any given source code module using a hierarchical class/attribute structure. All source lines occurring in a given module are partitioned into homogenous classes characterized by function or instruction type. Higher level programming concepts are abstracted from lower level implementation details by drawing correspondences between class members which constitute instruction sequences related by common elements. When inferencing begins, the existence of class members meeting certain criteria trigger events which change the state of the world as seen by the knowledge base, in turn triggering other state changing events and so on until a state of equilibrium is achieved.