Redesign strategies for digital VLSI circuits with incomplete implementation information

This paper deals with the problem of recovering the design of digital VLSI circuits with incomplete implementation information. A circuit is redesignable if the transfer function of the portion with incomplete implementation information can be derived cost effectively from the partially known information. The derived transfer functions are then used to re-implement the missing portions. We do not intend to discover the exact circuit schematic and components that were present in the circuit originally implemented. Rather, the functions originally intended to be present will be identical. The developed redesign process is comprised of three steps: redesignability check, feasibility check, and reimplementation. Based on the redesign process, experimental results on a number of MCNC benchmark circuits are reported