Structural FSM Traversal

A Compositional Approach to the Combination of Combinational and Sequential Equivalence Checking of Circuits Without Known Reset States

“…Specifically, Mony and coworkers at IBM have developed a framework for equivalence checking based on applying verification transformations [6], Huang and coworkers have constructed a sequential equivalence checker called AQUILA that uses ATPG and BDD techniques [2], and Stoffel et al have implemented a system that uses a representation of state spaces based on the queue of transformations that merge points [11]. Both AQUILA and the IBM equivalence checker use abstraction refinement and make use of combinational verification.…”

Utilizing don't care states in SAT-based bounded sequential problems

“…In BSEC, the problem is to verify that two designs implement the same function within a bound of a certain number of clock cycles k [18]. This method of sequential equivalence is especially effective when verifying retimed circuits or pipelined circuits.…”

“…Boolean Satisfiability (SAT) solvers are common engines in verification applications today [1] [9] [18].Much improvement has been made in the area of both general and problem specific SAT solvers [10] [12] [16]. One popular im-provement approach is exploiting problem specific information such as signal correlations [10], structural implications [17], BDD-based learning [2] [6], and circuit don't cares [14].…”

“…In BMC and BSEC problems, the sequential circuit is verified for correctness only within a finite number of clock cycles [1] [18], also known as a bound. The main advantage of these techniques is that they can often find counterexamples or errors in the design when other, more complete techniques fail due to resource constraints.…”

“…The rationale behind the recent success of these techniques arises from the fact that, in most cases, under normal operation a circuit is exercised only for a finite number of clock cycles. Overall, BMC and BSEC are popular techniques employed during design verification [1] [18].…”