An application specific processor for enhancing dictionary compression in Java card environment

Smart cards are low-end embedded systems used in the fields of telecommunications, banking and identification. Java Card is a reduced set of the Java standard designed for these systems. In a context of scarce resources such as smart cards, ROM size plays a very important role and dictionary compression techniques help in reducing program sizes as much as possible. At the same time, to overcome the intrinsic slow execution performance of a system based on interpretation it is possible to enhance the interpreter speed by means of specific hardware support. In this paper we apply the dictionary compression technique to a Java interpreter built on an application specific processor. Moreover, we move part of the decompression functionalities in hardware with the aim of speeding up the execution of a compressed application. We obtain a new interpreter that executes compressed code faster than a classic interpreter that executes non-compressed code.