[sv-bc] Event controls in always_comb?


Subject: [sv-bc] Event controls in always_comb?
From: Steven Sharp (sharp@cadence.com)
Date: Fri Oct 10 2003 - 17:39:26 PDT


The specification says in 9.4 that an always_ff block imposes the restriction
that only one event control is allowed.

However, 9.2 does not impose any restrictions on event controls in always_comb
blocks (aside from allowing tools to warn if the behavior does not represent
combinational logic, as it wouldn't if there were any event controls in it).
Was this intentional or an oversight?

Note that a blocking delay control in an always_comb block would also prevent
it from properly modeling combinational logic, since it would not respond to
its inputs while waiting at the delay control. The same is true of an
always_ff.

Steven Sharp
sharp@cadence.com



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