Low Power Java Processor for Embedded Applications

Abstract

This chapter presents a low power architecture of a Java processor. We show that the use of techniques like pipeline and the implementation of the stack in a register bank instead of using the main memory allow aggressive reduction of power dissipation, with a very small area overhead. Besides, thanks to the forwarding technique and to the specific stack machine organization, huge power savings can be obtained when applying this technique to a pipelined implementation of the architecture. Several examples of embedded applications are used to show the power savings obtained through the architecture optimization

Real-Time Operating Systems and Programming Languages for Embedded Systems

“…FemtoJava is a Java microcontroller with a reduced-instruction-set Harvard architecture (Beck & Carro, 2003). It is basically a research project to build an -application specific-Java dedicated microcontroller.…”

Hardware Support for Embedded Java

“…FemtoJava [6] is a research project to build an application specific Java processor. The bytecode usage of the embedded application is analyzed and a customized version of FemtoJava is generated in order to minimize the resource usage.…”

“…Based on CLDC, the real-time specification for Java (RTSJ) [8] defines a new memory model and strengthens the scheduling guarantees to enable Java for real-time systems. Safety-critical Java (SCJ) [30] defines a subset of RTSJ for safety-critical [31,63] Xilinx FPGA 15600 LC 14 KB 30 2002 FemtoJava [6] Xilinx FPGA 2700 LC 0.5 KB 56 2003 JOP [46,50] Altera, Xilinx FPGA 3000 LC 4 KB 100 2003 jamuth [65] Altera FPGA 33 2007 BlueJEP [15] Xilinx FPGA 6900 LC 0 KB 85 2007 SHAP [72,73] Altera, Xilinx systems. Most Java processors base the Java library on CLDC or a subset of it.…”

Cache-aware cross-profiling for java processors

“…There are several JVM hardware implementations, such as picoJava [22], aJile's JEMCore [16], Komodo [19], or FemtoJava [2]. Even though simulation tools are available for the processor design, profiling is not always possible and made only at the latest stage of development, i.e., on the actual processor.…”