A Java processor architecture for embedded real-time systems

Architectural advancements in modern processor designs increase average performance with features such as pipelines, caches, branch prediction, and out-of-order execution. However, these features complicate worst-case execution time analysis and lead to very conservative estimates. JOP (Java Optimized Processor) tackles this problem from the architectural perspective – by introducing a processor architecture in which simpler and more accurate WCET analysis is more important than average case performance. This paper presents a Java processor designed for time-predictable execution of real-time tasks. JOP is the implementation of the Java virtual machine in hardware. JOP is intended for applications in embedded real-time systems and the primary implementation technology is in a field programmable gate array. This paper demonstrates that a hardware implementation of the Java virtual machine results in a small design for resource-constrained devices.