Don't cares in synthesis: theoretical pitfalls and practical solutions

Weighted Don’t Cares

In this paper we introduce and discuss the new concept of weighted don’t cares, i.e., we propose to enrich the notion of don’t cares, by assigning them a weight. These weights might be used to guide and refine the choices operated by the minimization algorithms in handling the don’t care conditions. We then propose, and experimentally validate, the first synthesis tool for functions with weight...

Rapid Gate Matching with Don't Cares

Ending the logic synthesis, the technology mapping step maps the Boolean function on physical cells. This itep is based on a matching check, which complexity depends on the number of library cell inputs, and increases if don't cares are considered. The method presented here is based on fault analysis. Using a structural equivalent of the cell, it allows to prune dramatically the design space, a...

Redundancies and Don't Cares in Sequential Logic Synthesis

E cient Use of Large Don't Cares in High-Level and Logic Synthesis

This paper describes optimization techniques using don't-care conditions that span the domain of highlevel and logic synthesis. The following three issues are discussed: 1) how to describe and extract don't-care conditions from high-level descriptions; 2) how to pass don't-care conditions from high-level to logic synthesis; and 3) how to optimize the logic using don't-care conditions. E cient t...

On pattern matching with k mismatches and few don't cares

We consider the problem of pattern matching with k mismatches, where there can be don't care or wild card characters in the pattern. Specifically, given a pattern P of length m and a text T of length n, we want to find all occurrences of P in T that have no more than k mismatches. The pattern can have don't care characters, which match any character. Without don't cares, the best known algorith...