The SHAP Microarchitecture and Java Virtual Machine

This report presents the SHAP platform consisting of its microarchitecture and its implementation of the Java Virtual Machine (JVM). Like quite a few other embedded implementations of the Java platform, the SHAP microarchitecture relies on an instruction set architecture based on Java bytecode. Unlike them, it, however, features a design with well-encapsulated components autonomously managing their duties on rather high abstraction levels. Thus, permanent runtime duties are transferred from the central computing core to concurrently working components so that it can actually spent a larger fraction of time executing application code. The degree of parallelity between the application and the runtime implementation is increased. Currently, the stack and heap management including the automatic garbage collection are implemented this way. After detailing the design of the microarchitecture, the SHAP implementation of the Java Virtual Machine is described. A major focus is laid on the presentation of the layout and the use of the runtime data structures representing the various language abstractions provided by Java. Also, the boot sequence starting the JVM is described

Effiziente Mehrkernarchitektur für eingebettete Java-Bytecode-Prozessoren

Die Java-Plattform bietet viele Vorteile für die schnelle Entwicklung komplexer Software. Für die Ausführung des Java-Bytecodes auf eingebetteten Systemen eignen sich insbesondere Java-(Bytecode)-Prozessoren, die den Java-Bytecode als nativen Befehlssatz unterstützen. Die vorliegende Arbeit untersucht detailliert die Gestaltung einer Mehrkernarchitektur für Java-Prozessoren zur effizienten Nutzung der auf Thread-Ebene ohnehin vorhandenen Parallelität eines Java-Programms. Für die Funktionalitäts- und Leistungsbewertung eines Prototyps wird eine eigene Trace-Architektur eingesetzt. Es wird eine hohe Leistungssteigerung bei nur geringem zusätzlichem Hardwareaufwand erzielt sowie eine höhere Leistung als bekannte alternative Ansätze erreicht

An application specific Java processor with reconfigurabilities

Abstract — The paper presents an application specific Java processor including reconfigurabilities, which is a DLX like pipeline processor with 5 stages and executes Java byte codes directly. Reconfigurabilities are the key technologies for application specific operations. We have introduced two reconfigurabilities: (1) a mechanism to override the control signals for a specific instruction, (2) external components can be attached with the same input and output ports as the internal ALU. I