Assertion-based verification (ABV) is a methodology used in SystemVerilog to verify the functional correctness of a design by writing assertions. Assertions are statements that express a design property or behavior that must be true at a certain point in time during simulation. If the assertion is violated, the simulation will stop and report an error, allowing the designer to quickly identify and fix the problem.
The purpose of ABV is to provide a way to verify the correctness of a design in a systematic and automated way, reducing the time and effort required for verification. By writing assertions, designers can check that the design meets certain requirements and behaves correctly under different conditions.
Assertions are written using the “assert” and “assume” statements in SystemVerilog. The assert statement is used to specify a condition that must be true during simulation, while the assume statement is used to specify a condition that is assumed to be true during simulation. If an assert statement is violated, the simulation is stopped and an error is reported. If an assume statement is violated, the simulation continues, but a warning is issued.
Here is an example of an assert statement:
assert (a + b < 10) else $error("a + b should be less than 10");
In this example, the assert statement checks that the sum of "a" and "b" is less than 10. If this condition is not true during simulation, the simulation will stop and an error message will be printed.
Assertions can be used for a variety of purposes, including checking the correctness of a design, detecting design errors, and verifying that a design meets certain requirements. They can also be used to check the behavior of a design under different conditions, such as when inputs are changed or when the design is operating under different clock frequencies or power modes.