Question

The assert statement is used to enforce a property as a checker. When the property for the assert statement is evaluated to be true, the pass statements of the action block are executed. Otherwise, the fail statements of the action_block are executed. For example,

property abc(a,b,c);
    disable iff (a==2) not @clk (b ##1 c);
endproperty
env_prop: assert property (abc(rst,in1,in2)) pass_stat else fail_stat;

When no action is needed, a null statement (i.e.;) is specified. If no statement is specified for else, then $error is used as the statement when the assertion fails.

The action_block shall not include any concurrent assert, assume, or cover statement. The action_block, however, can contain immediate assertion statements.

Note: The pass and fail statements are executed in the Reactive region. The regions of execution are explained in the scheduling semantics section, Section 14.