嵌入式系統異質雙核心Java處理器設計

Abstract

Java執行環境已經慢慢地變成嵌入式多媒體系統的標準平台。這篇論文中，提出了為嵌入式系統所設計的異質雙核心Java處理器，其包含了普通的RISC處理核心以及一個雙指令Java處理核心。一些I/O，多媒體處理等程序交由RISC處理核心執行，而雙指令Java處理核心則是負責有效率地執行Java應用程式。特別要說明的是，在這個架構中並不包含一個功能完整的作業系統的支援，就可以執行Java應用程式。依據實驗數據，在相同的時脈下，本篇論文提出的異質雙核心Java處理器比Sun’s CVM在執行效率方面得到了8倍的提升，而與Google Android Dalvik相比下仍有4倍的提升。

Java Runtime Environment (JRE) is becoming the standard application platform for complex multimedia embedded systems today. In this thesis, we present the design of a dual-core Java application processor for embedded systems. The processor is composed of a generic RISC core and a double-issue Java core. The generic RISC core is responsible for running service routines to support Java tasks such as I/O requests, media accelerator logic invocations, floating point operations, etc. The double-issue Java core is in charge of execution of the Java applications and JRE. More importantly, the proposed system does not rely on any full-blown OS (such as Linux) running on the RISC. Only a thin kernel that maintains the execution of interrupt-driven Java service routines is necessary to support the JRE. A fast inter-processor communication mechanism based on the Java programming model is also proposed to reduce the overhead of invocation of service routines. Based on the implementation on a Xilinx Virtex-4 FPGA device, the Java execution performance of the proposed design is as much as 8 times faster than that of Sun’s CVM and 4 times faster than the reference implementation of Google Android-Dalvik VM running on a RISC processor at the same clock rate.