Assertion Statements - SVA: The Power of Assertions in SystemVerilog - page 80

Fig. 4.12 Assertion processing in regions

1. Event ( posedge e1) occurs, and
2. Signal ci_enb is true.
Otherwise, a new attempt of a2 is not fired off. However, the previous attempts
of a2 in progress are no longer coupled with (2); they are only sensitive to (1), hence
their evaluation is resumed should (1) occur.
Additional queues are called upon in the Observed region to schedule new
attempts and track other attempts that are in progress. Two queues, procedural
assertion queue and matured assertion queue are added in the Observed region to
dispatch the evaluation. The event semantics of procedural concurrent assertions is
described in greater detail in Chap. 14 .