Sequential permissible functions and their application to circuitoptimization

摘要

For sequential circuits the implementation freedom represented bycombinational permissible functions (CPFs) and un-reachable states don'tcares is not complete. We extend the concept of permissible functions tosequential circuits and introduce the sequential permissible functions(SPFs) to represent the complete freedom associated with a gate. We alsostudy and compare the relationship between CPFs and SPFs. In general,the computation of the SPFs is more expensive than the computation ofCPFs. We propose an algorithm that computes SPFs implicitly and is basedon the well-known state traversal approach. The computed SPFs are usedfor sequential circuit optimization