Sequential digital integrated circuits have stable state nodes that are
capable of retaining their state (logic value) even in the absence of any
input directly driving these points. However, in addition to stable state
nodes, some custom-designed digital circuits have so-called transient
state nodes. A transient state node is defined as node that can directly
affect the value of a stable state node and is combinatorially driven by
inputs of the circuit, but the transition delay from at least one input
to the node is greater than a predefined threshold value. Identifying
such transient state nodes, along with the stable state nodes, is
critical for the efficient simulation of custom digital circuits by a
hierarchical device level digital simulator. A method is provided herein
for identifying transient state nodes in a digital circuit, given the
circuit's netlist and the identity of the stable state nodes in the
circuit.