A unified numeric data type in Pascal

Abstract

It is proposed to substitute the standard data type real of a high level language, with a unified data representation which can include a variety of interpretations as well as formats, in order to allow experiments with an environment containing a spectrum of non-standard arithmetics, as well as standard. The implementation of a system is described where syntatic extensions to a language are made to support a microprogrammed virtual arithmetic unit which can treat variants such as integers, normalized, and unnormalized floating point numbers and intervals, within a unified representation.∗∗ More specifically Pascal is chosen as the base language, because it allows the user to define new data types, and the extension then mainly consists in substituting the simple (unstructured) data type real with a skeletal structured type (which will be called numeric). The system is intended to be implemented on a microprogrammable processor (called MATHILDA) with a 64 bit wide datapath. The language Pascal has already been partially implemented based on a stack machine specifically designed for that language, and realized by interpretation in microcode. The present compiler was constructed with the aid of a parser-generator system, which will allow the language extensions to be made with a moderate effort.