The Research And The Design Of The Java Processor For RTSJ

The property"Write once, compile anywhere"lets Java become a very popular programming language on internet. Java is platform-independent, object-oriented, multi-thread supported and safe, so it is widely used in internet. Meanwhile, Java is increasingly expected to become the leading programming language in embedded systems. But there is very few project using java in embedded system. There are two reason for that:⑴J ava virtual machine consume a lot of hardware resource;⑵Java program has unpredictable real-time behavior.Most of the embedded systems are real-time systems. Java technology is seldom used in embedded systems currently, due to the lack of acceptable real-time performance. To improve the real-time performance specified in the Java Language Specification and the Java Virtual Machine Specification, Greg Bollella et al propose the Real-Time Specification for Java (RTSJ).It provides a guideline for the implementation of real-time Java platform.Currently, to provide an efficient Java platform suitable for real-time applications, many different implementations are proposed. These implementations can be generally classified as Interpreter, Ahead-of-Time Compiler, and Java Processor etc. Java processor not only avoids the overhead of translation of the bytecode to another processor's native language, but also provides special support for Java runtime features such as stack processing, multithreading etc. Comparing with other implementing techniques, Java Processor is preferable in embedded systems for its high execution efficiency, low memory footprint and power consumption. Therefore, it becomes popular in implementing embedded real-time Java platforms.In the paper, we propose a simple-structured Java processor suitable for embedded real-time applications, which can fits into a low-cost FPGA. Meanwhile,we implemented the synchronization for RTSJ in software.The paper's main innovation is:1. Use stack based RISC processor to realation CISC based JVM2. The processor's microcode don't have relationship3. It can avoid priority inversion problem4. The processor has certain scalability; we can gradually add bytecodeThis thesis is divided into five parts. The first part introduces the Java virtual machine and the real-time specification for Java. The second part explains the detail hardware design of the java processor. The third part implements the wait-free synchronization in RTSJ. The fourth part gives the implementation and simulation. At last we discuss the subsequent work.