The TinyJ Processor family

(© Copyright Advancel Logic Corporation)

The TinyJ processor is the Java Card core offered by the Connecticut based Advancel Logic Corporation. It runs in two separate execution modes, native and Java. There is a simple mode switch that changes the execution from one mode to the other. Most Java bytecodes are handled directly in hardware. The exceptions are the more complex bytecodes referred to as 'long' bytecodes. These are trapped by the processor and emulated by executing software in native RISC mode. The processor is currently in the process of moving from implementing Java 1.1 to Java 2.

The core RISC engine has a four-stage pipeline for native execution mode (Fetch-Decode-Execute-Writeback). When in Java mode, there is an additional stage added to the pipeline that decodes the Java bytecode and translates it to be executed as the native equivalent (Fetch-Decode-Decode-Execute-Writeback)

MIPS 60 MIPS
CPU 32-bit RISC, speed 75MHz
Voltage 2.7 - 5.5 V
Memory 16 MB
Power dissipation < 10mW at 5.5V, < 0.1mW in idle mode
Size 2mm2 (small)
Flexibility Portable non application-specific design, flexible instruction set with instructions of size 1,2,3 or 4 bytes
Arithmetic Single-cycle 32-bit Multiplier allows DES encryption/decryption of 64-bit block in 0.015ms with just 200 bytes of code
Internal details Four/five-stage pipeline, 24-bit memory addresses, 16 GP registers, Four maskable interrupts, two memory buses for each of data and instructions

Perhaps even more important, Advancel provides a robust set of support tools and services for customization and software development, including software simulators, assembler, debugger, linker, loader, Java and C/C++ compiler, cryptographic librares and JavaCard VM classes and methods.

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References