RE: [sv-bc] Hierarchical reference in clocking signal

From: Jonathan Bromley <jonathan.bromley_at_.....>
Date: Wed Jul 11 2007 - 04:50:23 PDT
Surya raises a good point.

[Note: I've removed sv-ac from the list, and added 
sv-ec whose responsibility this is.]

> There is an e.g. in the LRM using hierarchical reference
>  as signal identifier (page no. 218)

Clause 15.8; in the new draft 3a it's clause 14.9.

> clocking cd1 @(posedge a.clk); 
>  input a.data; 
>  output a.write; 
>  inout state = top.cpu.state; 
> endclocking

> Which is wrong as per BNF.

Indeed it is.  It seems that this one slipped the net of 890;
I'm ashamed I didn't pick it up when EC was working on that.

If I don't hear a strong contrary opinion by the end of today,
I'll raise a Mantis item to fix this example and the associated
text.  I believe it is simply wrong.  The clockings should be
inside the interfaces, or else hierarchical_expression should
be used (as with the inout clockvar in the above example).  
Clockvars cannot have dotted names.

I believe the use of @(posedge a.clk) is OK according to 
the LRM, since it's an example of an "event_expression".
--
Jonathan Bromley, Consultant

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Received on Wed Jul 11 04:51:15 2007

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