Question

What are the three main types for formal verification and can you give names for industry tools in formal verification?

Answer 1

Formal verification:

Formal verification is that the overarching term for a set of techniques that use static analysis supported mathematical transformations to see the correctness of hardware or package behavior in distinction to dynamic verification techniques like simulation.

Equivalence checking:

Some styles of formal verification area unit already widespread in style. Equivalence checking has been used for quite a decade to see that RTL and gate-level descriptions of a style represent an equivalent style. Equivalence checking was introduced in response to the matter of larger styles olympian the effective capability of gate-level simulation tools, and quickly took over from hardware-acceleration solutions furthermore as software-only gate-level simulators. For users, the equivalence checking technology is comparatively straightforward to use within the manner it's been packaged by vendors, in tools such as Formality from Synopsys.

Model checking:

Model-checking formal verification is a lot of advanced to deploy because it not solely depends on user-generated assertions however on the proper choice of algorithms for a given downside. early formal verification tools additionally suddenly met difficulties on them as a result of the solvers, that were then, for the most part, supported equivalent binary call diagrams used in early equivalence checking tools quickly ran out of memory. It took a modification within the manner that multipliers can be delineated to try to made the duty of confirming them formally tractable.

SoC-level formal verification:

As typical verification has nonetheless to arrive associate degree exceedingly|in a very} form which will take a look at the complete behavior of an SoC, it has to be used as a part of a wider verification strategy which will embrace simulation and, possibly for big styles, emulation. Coverage management is a good mechanism for integration formal verification into a wider flow as, through the choice of applicable coverage points, it's doable to steer simulation vectors off from elements of the logic that have already been effectively tested by formal techniques.

Focused formal verification:

Clock domain crossing is an honest example of a vicinity of growing importance. federal agency has been with the USA for a protracted time, however, it's the proliferation of clocks in today’s SoCs that have seen it rise from, say, a third- to a first-order issue. styles with some clocks may need being addressed in simulation; people who currently have lots of area unit best verified during this respect before hand.

X-propagation is another application of formal techniques, and an honest example of one thing that presents issues for simulation. a lot of advanced styles area unit throwing out a lot of unknown states, which can cause bugs being misidentified or lost.

Tools:

— Lesar is a symbolic, BDD-based, model-checker for Lustre. Lesar being a model-Checker, verification is performed on associate degree abstract model of the program. Concretely, for strictly logical programs the proof is complete, whereas in general the proof is barely partial. to urge the tool see here.

— NBac is a security property verification tool, that analyzes synchronous and settled reactive systems containing combination of mathematician and numerical variables. NBac is predicated on the speculation of abstract interpretation, that permits the USA to beat the undecidability of the reachability/co-reachability downside for the category of programs treated by NBac. Sets of states area unit delineate by values happiness to associate degree abstract domain, and computations area unit performed. This results in conservative results: if a state is shown inaccessible, then it's obvious. a lot of details here.

— Gloups is associate degree automatic generator of PVS proof obligations. The tool performs a discount of the initial property expressed upon finite and infinite sequences into a collection of scalar properties: our leading principle for this reduction is induction. a lot of exactly, properties area unit expressed as Lustre observers and then reduced into a collection of scalar proof obligations that area unit discharged into the PVS theorem prover. associate degree proof of those obligations may be a proof of the initial invariant.

Those tools are used with many industrial case studies from EADS, Airbus, Schneider, etc. you'll be able to realize a lot of details here.