Automatic classification of node types in switch-level descriptions

In switch-level simulation, nodes carry a charge on their parasitic capacitance from one evaluation to the next, which gives them a memory quality. A node is classified as temporary if its memory aspect is lost and cannot affect the circuit operation, whereas a node is classified as a memory node if the memory of the node is maintained and can affect the circuit operation. Accurate classification of nodes into temporary and memory nodes increases the performance of compiled simulators and high-level model generators. An approach for reliable automatic classification of nodes in a switch-level description is introduced. Both an exhaustive, exponential-time algorithm and a polynomial-time heuristic are presented. The heuristic was implemented and tested for several large circuits, including a commercial microprocessor. For this processor, the proposed heuristics identified an average of 92% of all nodes as temporary nodes. The heuristic was applied in a high-level model generator and significantly increased its performance