Experience with porting techniques on a COBOL 74 compiler

ABSTRACT

The problems of compiler construction have largely been solved for COBOL '74, but a remaining fundamental consideration in a commercial environment is the cost of compiler development. This can be reduced by the use of portable software, but the cost of porting to a new system remains significant. In the microprocessor system market, two approaches have been followed. The first is to produce software for a virtual machine environment and simulate this on real hardware be means of an interpreter. Most software, including language processors and large parts of the operating system, can be transferred almost unchanged to a new processor. Nearly all commercial software for microprocessors has been developed on this basis. The alternative approach is to produce software which, by virtue of certain characteristics, can be made to be portable to new real machine environments, provided the appropriate high level language compiler is available. We have developed an ANS COBOL 74 compiler for microprocessors using this second approach [1]. Since the compiler compiles COBOL at a level approaching level 2 in the main modules to the true machine code of the target machine, the same approach becomes available to the applications programmer. As far as can be established, this work is unique. Both compiler and object code interface directly to the machine environment. No interpreter is required for their execution. The compiler system runs on, and generates code for, three machines. In addition, since the compiler is written in a high level language, portable cross compilers are available.

REFERENCES

• 1: L. Hirschmann: CDL2 im industriellen Einsatz, Gesellschaft für Mathematik und Datenverar-beitung, Bonn, IST-Bericht Nr. 45, 1980 (in German).
• 2: J.P. Dehottay, H. Feuerhahn, C.H.A. Koster, H.M. Stahl: Syntaktische Beschreibung von CDL2, TU Berlin, Fachbereich 20, Forschungsgruppe Softwaretechnik, 1976 (in German).
• 3: H.M. Stahl: Portability and Efficiency in Using an Open-Ended Language, Applied Informatics Nr. 5, 1979.

INDEX TERMS

Primary Classification:
  D. Software
  D.3 PROGRAMMING LANGUAGES
      D.3.2 Language Classifications

          Nouns: COBOL

Additional Classification:
  D. Software
  D.3 PROGRAMMING LANGUAGES
      D.3.4 Processors
          Subjects: Compilers

General Terms:
Languages