Reverse Engineering Technology as a Tool of Embedded Software: A Solution fromPL/M Code to Structure Charts

摘要

The number of real-time computer systems in which embedded software has been usedhas dramatically increased during the eighties. Many such systems have now been used from ten to sixteen years. The oldest embedded software applications now being maintained were developed without the help of any high-level design languages, advanced methods and CASE tools. Reverse engineering has, therefore, become a viable means for improving the maintainability of embedded software. This study introduces reverse engineering as a technology that can be used in the maintenance of embedded software. The technologies were adopted in a reverse engineering tool, which is able to produce structure charts automatically from PL/M programs. Syntax analysis is introduced as a principle solution to extract data required in the derivation of the charts. Since structure charts are language oriented descriptions, the data can be easily transformed to structure charts compatible with a commercial CASE environment. The framework of knowledge-based functional analysis, as well as its implementation that is partially automated, is described. In addition to the description of reverse engineering technology, this study discusses the process of preventive maintenance, where the technology is used.