A Java processor suitable for applications of smart card

Starting from the Java Card Virtual Machine (JCVM) specification and the picoJava-II architecture, a pipelined Java card processor has been designed. It implements all of JCVM bytecodes with 16-bit operands in three different ways according to the complexity of their functions. It utilizes a one-read one-write dual-port RAM as Java stack in order to reduce the consumption of limited memory footprint on a smart card. It also includes a Smart Card extension instruction set, which is used to support the low-level hardware operations required by Smart Card Operating System (SCOS). An assembler for this processor is developed, and a simple SCOS with 10 APDU commands is written. The SCOS is simulated in a simulation environment based on the HDL model of this processor. Then the processor with an ISO standard serial I/O port is implemented and verified on a hardware verification system based on FPGA. The results of real interactions with card reader show that this processor can meet the requirements of smart card applications.