Instruction execution method of Java card virtual machine

Abstract

The invention relates to an instruction execution method for a Java card virtual machine, comprising the steps as follows: step one, a processor executes the current instruction which is required to be executed in an instruction set; meanwhile, an accelerator is informed by the processor to analyse the current instruction; step 2, the accelerator analyses the property of the current instruction and obtains the byte code address of the next instruction; steps 3, the processor is informed of the byte code address of the next instruction and jumps to the next instruction after completing the execution of the current instruction. The instruction execution method for the Java virtual machine provided by the invention carries out the analysis of the current instruction by the accelerator and obtains the byte code address of the next instruction, leads the processor to directly jump to the next instruction required to be executed immediately after completing the execution of the current instruction and has the advantages of high efficiency and high stability.

Description

technical field [0001] The invention relates to the field of smart cards, in particular to an instruction execution method of a Java card virtual machine. Background technique [0002] Smart cards have been widely used in various products such as mobile phones, music players, and digital TVs. Smart cards can realize various functions such as identification, data storage, and information processing. Java Card is a new smart card and an open multi-application platform, through which various applications can be downloaded. [0003] Because the Java card itself has the characteristics of the Java language, it interprets and executes instructions through the Java card virtual machine. The Java Card virtual machine is not a physical structure, but an independent operating environment that interprets the bytecode for the hardware platform, where the bytecode is interpreted by selecting the original machine language stored in the memory or CPU instructions are realized. For the J...

AI Technical Summary

Problems solved by technology

[0004] figure 1 A method for executing instructions of an existing Java Card virtual machine is disclosed in figure 1 In the instruction register 11 shown in , an instruction set consisting of four instructions P1, P2, P3, and P4 is stored, and the CPU 12 interprets (that is, in the order of P1, P2, P3, and P4) and executes each instruction in sequence through sequential execution. However, the execution method of this instruction is very time-consuming. For example, if the CPU 12 needs to execute the next instruction P4 after executing the instruction P1, the CPU 12 still needs to interpret the instructions P2, P3 until P4. Explain until the instruction that needs to be executed is found, this method will greatly affect the running speed of the Java card, and the efficiency is very low

On the other hand, if an exception or error occurs during the execution of a certain instruction, then the CPU 12 cannot continue to execute the next instruction, which will cause a crash, resulting in low stability of the Java card.

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