LISP-based "big-float" system is not slow

  • Authors:
  • Yasumasa Kanada;Tateaki Sasaki

  • Affiliations:
  • Nagoya University, Chikusaku, Nagoya, Japan;The Institute of Physical and Chemical Research, Wako-shi, Saitama, Japan

  • Venue:
  • ACM SIGSAM Bulletin
  • Year:
  • 1981

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Abstract

The efficiency of evaluation is investigated on two "big-float" systems, our LISP-interpreter-based system and Brent's FORTRAN-compiler-based system. The test problems are computations of constants e and pi, and functions sqrt(x) and exp(x). We found that speeds of big-float addition, subtraction and multiplication on our LISP-based system are nearly the same as or rather faster than those on the FORTRAN-based system. This high efficiency of basic arithmetic operations in our system is essentially due to the efficient big-integer routines in a host LISP-system written in an assembly language. Evaluation speeds of the test problems themselves on the LISP-based system are, on an average, 1.5 times slower than those on the FORTRAN-based system. The ratio of the evaluation speeds depends, however, very much on how the routines of test problems are programmed. Therefore, we conclude that the speed of a LISP-based big-float system can be reduced to within two times of that of a FORTRAN-based system.