Proposal for Extension of JavaTM Floating Point

Prompted by feedback from several partners in the industry, Sun is proposing a change to the specification of floating-point in the Java programming language. The current Java programming language and virtual machine specifications require that all single and double precision floating-point calculations must round their results to the IEEE 754 single and double precision formats, respectively. The intent of this proposed change is to permit additional floating-point calculations to be done using IEEE 754 extended precision formats. Informally, extended precision means precision that is at least as great as that required by Java programming language types. By making this change, processors that more naturally and efficiently support extended precision formats and floating-point operations on extended precision formats can deliver better performance for floating-point calculations. Processors that naturally and efficiently implement IEEE 754 single and double precision operations as previously mandated by the specifications may continue to do so. In particular, this proposal does not invalidate the class file format. Any Java virtual machine implementation that conforms to the current specification conforms to the proposed new specification. The proposal affects both the definition of the Java programming language, in The Java Language Specification, by Gosling, Joy, and Steele, and the definition of the Java virtual machine, in The Java Virtual Machine Specification, by Lindholm and Yellin. In addition, the proposal implies changes for Java platform compatibility testing and for compilers for the Java programming language.