Apparatus and method for removing effects of phase abstraction from a phase abstracted trace

Abstract

An apparatus and method for automated use of phase abstraction for enhanced verification of circuit designs is provided. With the apparatus and method, latches are “colored,” i.e. classified into different types, based on information obtained from a clock tree of the circuit design. Clock tree primitives contain sufficient information to taxonomize the clocks into their respective phases and identify which latches are gated latches. In coloring the latches, gated latches are replaced in the circuit design with a free running clock, a multiplexor, and a sequence of L1 to Ln latches to provide a feedback path via the data path. This allows the gated latch to be phase abstracted without losing the “gated” functionality of the gated latch in the resulting trace. Once the latches are colored in this way, phase abstraction is performed on the colored circuit design. The phase abstracted netlist is then subjected to verification and a trace is produced. The coloring information of the original circuit, plus information as to the exact nature of the phase abstraction performed, is then used to transform the phase abstracted trace to one which resembles a trace of the circuit without phase abstraction.

Dependencies are inferred from the claim text.