Method for automatically generating checkers for finding functional defects in a description of circuit

Abstract

A programmed computer generates descriptions of circuits (called 'checkers') that flag functional defects in a description of a circuit undergoing functional verification. The programmed computer automatically converts the circuit's description into a graph, automatically examines the graph for instances of a predetermined arrangement of nodes and connections, and automatically generates instructions that flag a behavior of a device represented by the instance in conformance with a known defective behavior. The checkers can be used during simulation or emulation of the circuit, or during operation of the circuit in a semiconductor die. The circuit's description can be in Verilog or VHDL and the automatically generated checkers can also be described in Verilog or VHDL. Therefore, the checkers can co-simulate with the circuit, monitoring the simulated operation of the circuit and flagging defective behavior. The programmed computer can automatically determine load conditions of registers in the circuit and automatically generate checkers to flag data loss in the registers. Some of the checkers may use signals generated by other checkers.