Computing the area versus delay trade-off curves in technology mapping

We examine the problem of mapping a Boolean network using gates from a finite size cell library. The objective is to minimize the total gate area subject to constraints on signal arrival time at the primary outputs. Our approach consists of two steps. In the first step, we compute delay functions (which capture gate area-arrival time tradeoffs) at all nodes in the network, and in the second step we generate the mapping solution based on the computed delay functions and the required times at the primary outputs. For a NAND-decomposed tree, subject to load calculation errors, this two-step approach finds the minimum area mapping satisfying a delay constraint if such solution exists. The algorithm has polynomial run time on a node-balanced tree and is easily extended to mapping a directed acyclic graph (DAG). We also show how to account for the wire delays during the delay function computation step. Our results compare favorably with those of MIS2.2 mapper.