A Management Scheme for the Basic Types in High Level Languages

Abstract

This note describes a type concept for the basic data types handled in the applications of digital systems, numbers and bit fields, which are usually predefined in higher level languages and serve as the basis for application spe-cific data types and classes. It has been implemented in a real-time language for parallel embedded systems and is motivated by the fact that such systems may have to use a multitude of application-specific number types. The type concept actually applies to programming languages for all classes of applications. It pro-poses the use of an abstract data type of numbers for which the various enco-dings of numbers provide implementations. This simple approach not only allows non-standard encoding types to be added as needed but also provides common formats for input and output and derived numeric data types that aren’t bound to a specific encoding. Related to the handling of the basic data types is a conversion policy. For bit fields, conversions are substituted by word number changes of multi-word codes. Finally, the abstract number type can be used to simplify the related typing of functions that no longer need to specify the encoding of all their arguments and results.