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CHAPTER 6 Logic synthesis in a nutshell > 6.2 Data Structures for Boolean repre... - Pg. 302

302 CHAPTER 6 Logic synthesis in a nutshell highly productive IC design methodology. Commercial logic synthesis tools evolve and continue to incorporate developments addressing new design challenges. The scope of logic synthesis can be identified as follows. An IC may consist of digital and analog components; logic synthesis is concerned with the digital part. For a digital system with sequential behavior, its state transition can be implemented in a synchronous or an asynchronous way depending on the existence of synchronizing clock signals. (Note that even a combinational circuit can be considered as a single-state sequential system.) Most logic synthe- sis algorithms focus on the synchronous implementation, and a few on the asyn- chronous one. A digital system can often be divided into two portions: datapath and control logic. The former is concerned with data computation and storage, and often consists of arithmetic logic units, buses, registers/register files, etc.; the latter is concerned with the control of these data processing units. Unlike control logic, datapath circuits are often composed of regular structures. They are typi- cally laid out manually by IC designers with full custom design to ensure that design constraints are satisfied, especially for high performance applications. Hence datapath design involves less logic synthesis efforts. In contrast, control