Subject: Re: Java Grande Concurrency Special Issue Resent-Date: Sun, 08 Aug 1999 06:38:15 -0400 Resent-From: Geoffrey Fox Resent-To: p_gcf@npac.syr.edu Date: Sun, 08 Aug 1999 13:42:26 +0900 From: Yutaka OIWA To: Geoffrey Fox I am sorry I have sent previous mail in unusual "split" format. I resend the same mail with unsplited format. If you could read the previous mail correctly, please ignore this mail. === I am Yutaka OIWA in the University of Tokyo. I submit a paper to the journal special issue. I am very sorry that I have not submitted this in daytime. The paper is attached to this mail in PostScript format with zip compression. Thank you. Title: Extending Java Virtual Machine with Integer-Reference Conversion Authors: Yutaka Oiwa, Kenjiro Taura, Akinori Yonezawa University of Tokyo Abstract: Java virtual machine (JVM) is an architecture-independent code execution environment. It is recently used not only for Java language but also for other languages such as Scheme and ML. On JVM, however, all values are statically-typed as either immediate or reference, and types are checked before the execution of a program to prove that invalid memory access will never occur. This property sometimes makes implementation of other languages on JVM inefficient. In particular, implementation of dynamically-typed language is very inefficient because all possible values including frequently-used ones such as integers must be represented by instances of a class. In this paper, we introduce a new type into JVM, which is a supertype of reference types and a tagged integer type. This allows a more efficient implementation of dynamically-typed language on JVM. It does not require any new instruction, maintains binary-compatibility of existing bytecode, and retains the safety of the original JVM. We modified an existing Scheme system running on JVM to exploit this extension and got factor of 20 speedup for simple integer functions. Our extension imposes little performance penalty on existing JVM code generated from Java; we observed essentially no penalty for Spec JVM benchmarks. -- Yutaka Oiwa Yonezawa Lab., Department of Information Science, Graduate School of Science, University of Tokyo. Email: , PGP fingerprint = C9 8D 5C B8 86 ED D8 07 EA 59 34 D8 F4 65 53 61 --------------------------------------------------------------------- Name: journal.zip journal.zip Type: Zip Compressed Data (application/x-zip-compressed) Encoding: base64