The invention relates to a software system and method for automatically verifying the correct execution of an application ported from one instruction set architecture (ISA) to another ISA. In this method, versions of the application are prepared for the two ISAs. Each version is then executed in a simulator or emulator for the appropriate ISA and the results of any change in memory made during the execution are compared. If each memory change made during the execution of the target version of the application is found to be equivalent to a memory change made during the execution of the source version of the application, the execution of the target (or ported) application is verifiably correct.