The Research And Design Of JCVM Interpreter

With the construction of China's information-depth development, the smart card is used more and more widely in various industries in China. With further normalization for the smart cards technology and smart cards applications, Java Card technology become the focus of research and development in smart cards field for its characteristics of platform-independent, multi-application and the dynamic download. Java Card Specification is a guidance of a programmatic document that gives guiding principles in building a Java card, but did not gives the details of building Java Card. Therefore, building a Java Card's method is likely to vary, or even very different. How to implement the basic requirements of Java Card Specification, and to ensure the efficiency and robustness of Java Card as far as possible is the main research issues。In the Java Card architecture, the most critical is the Java Card Virtual Machine. The interpreter is the core of Java Card Virtual Machine, which is responsible for interpreted Java application byte code after conversion. Main objective of this paper is to study Java Card Virtual Machine, and to design and implement a Java Card Virtual Machine interpreter that consists with Java Card Specification.Firstly, through the analysis for the Java Card Virtual Machine model,this paper explains the realization of the key issues in a Java Card Virtual Machine interpreter. We analyze the Java Card Virtual Machine Mainly through the type of data, runtime data area, and the binary representation EXP file format and CAP file format related to the Java Card Virtual Machine. And then we design the registers, Java stack, heap and exception handling of the interpreter, and specifically given the process of design and the realization of the instruction set.In the process of the design and implementation,this paper achieves the dynamic Java stack to expand and contract through a serial link; we improve the efficiency of the interpreter by way of instruction prefetch; save space and simplify the parameters passing of the method call through the sharing mechanism. Finally, the test of the interpreter indicates that the Java Card Virtual Machine interpreter can achieve the functional requirements of the Java Card Virtual Machine Specification 2.2.2, and the interpretation can execute the Java Applet programs that consist with Java Card Specification 2.2.2.The contents of this research is a useful attempt in developing proprietary Java Card products, but also provide and accumulate the relevant experience and information for Java Card technology and application of further research.