Bus-Switch coding for reducing power dissipation in off-chip buses

Compression of executable code in embedded microprocessor systems, used in the past mainly to reduce the memory footprint of embedded software, is gaining interest for the potential reduction in memory bus traffic and power consumption. We propose three new schemes for code compression, based on the concepts of static (using the static representation of the executable) and dynamic (using program execution traces) entropy and compare them with a state-of-the-art compression scheme, IBM’s CodePack. The proposed schemes are competitive with CodePack for static footprint compression and achieve superior results for bus traffic and energy reduction. Another interesting outcome of our work is that static compression is not directly related to bus traffic reduction, yet there is a trade off between static compression and dynamic compression, i.e., traffic reduction.