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Author: Admin | 2025-04-28
Entry with the same row and burst.4. If the entry exiting the queue is not of the same row, the next entry exiting the queue should not be the E1 unless N1 is 1.5. No entry should exit after E1 if N1 is 0.Applying this approach breaks down the problem into several smaller properties, rather than one reference model. With specification changes, many of the properties are still applicable. We simply need to add and delete properties to the existing set. Therefore, proper planning and methodology can enable successful formal verification deployment.Applicable and non-applicable functions Formal verification applies to arbiters, although few apply it properly for complex arbitration schemes. For example, the arbitration priority of a port increases upon certain events and decreases upon other events. To consider all those events for all ports makes the property quite complicated.We should instead be looking at the arbiter as two separate sets of functions: (1) the arbitration scheme is based on the current priorities of the ports and (2) certain events increase and decrease the priority. If the two functions are verified by separate properties, it becomes two rather simple problems.Moving up one level of abstraction, an arbiter is actually one form of decoder that, when properly applied, has a relatively small sequential depth (referring to the number of cycles it takes to reach all the states within the arbiter). Consider the following example.Figure 3 — Arbiters and decoders This example brings us to a myth in formal functional verification:Myth 1: Decoders are not suitable for formal verification. Arbiters are generally considered one of the sweet spots for formal verification. And if we consider arbiters as a form of decoder, we contradict this generally accepted statement. The key to applying formal to decoders is to apply it in isolation. Another consideration for decoder verification is how implementation-specific the decoder properties are — if the decoder is not an area of concern, in that the decoding function is very implementation specific, there might not be a need to apply formal. Some decoders simply decode the address space to determine a hit or miss,
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