On the estimation of logic complexity for design automation applications

Many logic design automation procedures would benefit from a priori knowledge of complexity of the resulting realization. There are no universally accepted notions of space/time complexity criteria, as such measures are greatly influenced by the target topologies and technology. Even though an accurate measure of logic complexity is extremely difficult to compute, it is possible to obtain rough estimates of relative logic complexities with the use of simple estimators. It is shown that functional complexity criteria are very reliable as relative predictors of logic complexity for functions in particular classes (such as adders, arithmetic functions, etc.) or functions that otherwise have similar structures but do not perform as well when random functions are considered. The functional complexity criterion used in this study can relate the complexities of two adders with different number of bits very well, but cannot predict the relative complexities of two functions in entirely different classes.<<ETX>>