Incremental synthesis for engineering changes

The problem of rectifying design incorrectness due to specification changes as well as design errors of VLSI circuits is formulated and a basic approach using logic synthesis techniques is presented. An efficient approach is presented for rectifying the functional incorrectness by attaching circuitry exterior to the original design. A necessary and sufficient condition for full rectification of the design is provided. It is shown that the proposed approach always succeeds in the rectification of arbitrary combinational circuits. The situation where rectification arises in a practical design process is briefly reviewed