VLSI circuit: Design using APL with fortran subroutines

Abstract

Our group at IBM Yorktown Research has written a number of tool programs for VLSI design, all in APL. Several crucial algorithms were speeded up by recoding them in Fortran and Assembler Language. For example, the algorithm for complementation of a Boolean expression (which can sometimes have thousands of terms in dozens of variables) is 5 times faster in Fortran than the best APL code I could write. The linking mechanism used from APL to outside languages is the experimental AP403 from IBM Heidelberg, though other similar auxiliary processors exist (e.g. the IUP AP999). Thus, each language, Fortran and APL, is used to its best advantage: Fortran for raw speed, and APL for interactiveness and ease of coding.