METHOD AND DEVICE FOR MODIFYING LOGIC EXPRESSION IN LSI LOGIC DESIGN, AND RECORDING MEDIUM FOR MODIFYING PROGRAM FOR LOGIC EXPRESSION IN LSI LOGIC DESIGN

摘要

PROBLEM TO BE SOLVED: To provide a method and device for modifying a logic expression in an LSI logic design which can modify the original logic expression into two new logic expressions having a small number of inputs while maintaining a structure with good properties in the original expression with a relatively small calculation quantity even for a large-scale logic function, and also to provide a recording medium where a modifying program for the logic expression in the LSI logic design is recorded. ;SOLUTION: A function calculation part 3 calculates a logic function (f) that a logic expression F represents and a decomposition decision part 5 determines whether or not decomposition f(X, Y)=h(G(X), Y) having no repetition of a variable is present in the calculated logic function (f). When the decomposition exists logic functions df₀(Y), df₁(Y), and g(X) are outputted, and a part 7 to constitute an expression G constitutes a logic expression G of a function g(X) from the logic expression F and logic functions df₀(Y) and df₁(Y), and a part 9 to constitute an expression H constitutes a logic expression H of the logic function h(g, Y) from the logic expression F and logic function g(X).;COPYRIGHT: (C)1999,JPO