Embedded systems generally interact with the outside world. Thus, some real-time constraints may be imposed on the system design. Verification of these constraints requires computing a tight upper bound on the worst case execution time (WCET) of a hardware/software system. The problem of bounding WCET is particularly difficult on modern processors, which use cache-based memory systems that vary memory access time significantly. This must be accurately modeled in order to tightly bound WCET.

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... ting approaches either search all possible program paths, an intractable problem, or they use pessimistic assumptions to limit the search space. In this paper we present a far more effective and accurate method for modeling instruction cache activity and computing a tight bound on WCET. It is implemented in the program cinderella. We present some preliminary results of using this tool on sample embedded programs.