Subject: [sv-ec] Testbench clocking note
From: Adam Krolnik (krolnik@lsil.com)
Date: Wed Dec 11 2002 - 09:05:09 PST
Good morning;
I have two comments about the section 13.10 and 13.11
For the default clocking specification, why not allow the keyword 'default'
to be a prefix of a clocking domain definition.
E.g.
default clocking bus @(posedge clk)
...
endclocking
The reader thus knows the default domain once they have viewed all the domains.
On the cycle delay operator, "##". It seems to me that this operator is too
visually close to the '#' (delay) operator.
We have seen several cases where users expected to use the identity operator "==="
and ended up with the comparison operator "==" simply because read almost
the same.
The proposed "##" operator also is visually similar to the delay operation and
could easily be mistyped. Thus one who intended a cycle delay
will receive a timestep delay.
E.g.
##5;
send_out = 1;
#5;
check_results();
As an alternative, what about using the event control operator '@' which more naturally
matches counting clocking events. E.g.
@5;
send_out = 1;
@5;
check_result();
Note that this currently is a syntax error - you can't use a constant with event control.
Thanks.
Adam Krolnik
Verification Mgr.
LSI Logic Corp.
Plano TX. 75074
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