Accession Number : AD0905272

Title :   Aerospace HOL Computer. Volume II. Direct Execution Tradeoffs.

Descriptive Note : Final rept. Jun 71-Nov 72,

Corporate Author : LOGICON INC SAN PEDRO CA

Personal Author(s) : Nielsen, William C. ; Vere, Steven A.

Report Date : OCT 1972

Pagination or Media Count : 110

Abstract : This volume presents an analysis of higher order language computer architectures. These architectures execute an HOL directly without the aid of a compiler. The implications of directly implementing six scientifically oriented HOLs (FORTRAN, ALGOL, JOVIAL, APL, and SPL and PL/I) are discussed, making use of a method which formally specifies the syntax and semantics of these languages. It was found that the gross number of features in a language had the most influence on the degree of implementation difficulty, with PL/I and SPL/Mark IV being the two largest languages and FORTRAN IV and ALGOL 60 the smallest. Ramifications of preprocessor implementation were analyzed, the preprocessor being an assemblerlike software tool for converting the HOL source program to its internal memory form. Preprocessor/architecture tradeoffs were discussed and a set of recommended proprocessor transformations was prepared. These included removal of blanks and comments from the source program, and the conversion of symbolic names to machine addresses. Problems designing and programming the preprocessor were analyzed. The Appendices in this volume contain a description of the SPL/MARK IV subset for which an architecture has been designed, an analysis of optimal storage retrieval schemes, and an introduction to the transduction equation concept used in designing an architecture for SPL. (Author)

Descriptors :   (*PROGRAMMING LANGUAGES, SPACEBORNE), COMPUTER LOGIC, MEMORY DEVICES, PROGRAMMERS, SUBROUTINES, COMPILERS, DATA PROCESSING, OPTIMIZATION.

Subject Categories : Computer Programming and Software
      Computer Hardware

Distribution Statement : APPROVED FOR PUBLIC RELEASE