Region Definition and Ordering for Macrocells with Unconstrained Placement

The design of complex VLSI circuits is typically based on the decomposition of the routing area into regions to be connected independently of one another. This approach requires the use of a tool for the definition of these regions and their ordering through a suitable interconnection sequence. In this paper, an algorithm is proposed that is able to successfully define and order routing regions for generic macrocell structures in which non-rectangular blocks are utilized. The ordering scheme involves the building and management of a floor plan graph to extract the intrinsic dependence among regions. The program produces the complete specification of each routing region, the information of which type of routing tool can be used for connecting each routing region (channel or switchbox), and the order according to which regions will be connected.