Being the device which draws up the truth value chart which shows the relationship

摘要

PROBLEM TO BE SOLVED: To efficiently prepare a truth table for a combinational logic circuit. ;SOLUTION: An input signal sequence is prepared (S1) by arranging plural input signal patterns in certain order so that a humming distance can become '1' before and after, and the input signal patterns are successively extracted from the top one by one (S2). As for the first extracted pattern, processing for generating an output signal pattern is performed by propagating the input signal to all the logic gates inside the logic circuit (S4) and concerning the pattern extracted for the (n) time (n1), processing for updating the output signal pattern is performed by specifying one input bit having a logic value different from that of the pattern extracted in (n-1) time and propagating the input signal only through the logic gate affected by this input bit (S5). The respective input signal patterns and the generated or updated output signal patterns are made correspondent so that the truth table can be prepared (S6).;COPYRIGHT: (C)1997,JPO