A language-oriented instruction set for the BALM language

Abstract

The availability of microprogramming has increased interest in the design of instruction sets which are oriented towards particular higher-level languages (see (1), for example). We will refer to these as language-oriented instruction sets (or LOISs). In this paper we give a formal definition of a LOIS for the extendable language BALM. This LOIS, which we call MBALM, is used as the basis of the implementation of the current version of the language, BALM4. We will also compare two implementations of the MBALM instruction set, and outline briefly our experiences with them. The external description of BALM4 is given in detail elsewhere (2,3). Briefly, it is an extendable language with an Algol-like syntax and data-types integer, real, logical, string, pair (list), vector, identifier, procedure, and label. Type information is carried with all data-objects, and run-time type testing and conversion is done when necessary. Garbage collection and a run-time compiler are significant attributes of the system. Outlined below are some of the properties of the implementation, which was designed initially for reasons of simplicity and flexibility, but which illustrate some of the advantages of a LOIS-based system.