OPTOELECTRONIC SYMBOLIC SUBSTITUTION BASED CANONICAL MODIFIED SIGNED-DIGIT ARITHMETIC

A single-step optoelectronics symbolic substitution scheme to handle p arallel modified signed-digit (MSD) arithmetic operations is proposed, Conversion algorithms from MSD numbers into a canonical MSD represent ation are provided. The canonical MSD numbers have the property that n o two consecutive digits are non-zero, The addition operation of two C MSD numbers is performed in one step. It will be shown that through th e use of CMSD representation, the number of symbolic substitution rule s in an optical content-addressable memory (CAM) based system is signi ficantly reduced, The number of symbolic substitution rules can be fur ther reduced to an optimum value through a proposed shared content-add ressable memory optical set-up. Further, the proposed optical scheme d oubles the storage efficiency of the shared content-addressable memory . (C) 1997 Elsevier Science Ltd.