AutoFix: A hybrid tool for automatic logic rectification

We address the problem of rectifying an erroneous combinational circuit. Based on the symbolic binary decision diagram techniques, we consider the rectification process as a sequence of partial corrections. Each partial correction reduces the size of the input vector set that produces error responses. Compared with the existing approaches, this approach is more general, and thus, suitable for circuits with multiple errors and for the engineering change problem. Also, we derive the necessary and sufficient condition of general single-gate correction to improve the quality of rectification. To handle larger circuits, we develop a hybrid approach that makes use of the information of structural correspondence between specification and implementation. Experiments are performed on a suite of industrial examples as well as the entire set of ISCAS'85 benchmark circuits to demonstrate its effectiveness.