The Research On Porting JVM Based On ARM7/uClinux

Java Virtual Machine was one of core technologies in Java, which was the basic of "platform-independent" characteristic. Kaffe virtual machine was a clean-room and open source Java Virtual Machine, Which was good choice to execute Java application in open source embedded systems. But currently Kaffe did not support the embedded processors and operating systems which were MMU (Memory Management Unit)-Less to simplify the system, so the purpose of this paper was to port Kaffe to ARM7/uClinux that was popular embedded platform, by modifying some characteristics and adding related class libraries in Kaffe, building "Java runtime environment" to make Java applications run on it.New files of platform configuration and initialization were established for Kaffe in paper, platform-related documents which were kernel of Kaffe like interpreter and just-in-time compiler were improved and modified. According to the characteristics such as length of the instructions and data types of ARM7, data structure of Kaffe was reset. According to MMU-Less characteristic of ARM7 and uClinux, new macro operations were defined in Kaffe profile to assist ARM7 accessing memory, and memory management approach in local methods was searched by GLIBC. Because ARM7 used FPA (floating-point co-processor) and VFP (vector floating point co-processor) which were two different floating point units and Kaffe supported FPA only, different mechanism were designed for supporting VFP in Kaffe.Results from JMocha and SciMark tools that were used to test system for reserch above showed that improved Kaffe could run on MMU-Less Embedded Platform ARM7/uClinux, and could execute Java applications. Finally, data of Kaffe was compared with Wonka virtual machine in the paper, results proved that Kaffe did not only have speed advantage in some operations, but also had character-dynamic-concat and string-concat functions that Wonka did not have.