[sv-ac] RE: Concurrent assertions in always procedures

Hi Dimitry,

 

When I look at 9.2 section (draft4), it has:

 

- always procedures, denoted with the keywords:

- always (see 9.2.2.1)

- always_comb (see 9.2.2.2)

- always_latch (see 9.2.2.3)

- always_ff (see 9.2.2.4)

 

Section 16.14.5 is not using the same font as the font of generic always
in 9.2. 

 

I am not so much familiar with fonts being used in LRM. But I do see
statements in 16.14.5 which implicitly imply that concurrent assertions
can not be embedded in always_comb. Here is one statement from this
section:

 

A concurrent assertion embedded in procedural code specifies that a new
evaluation attempt of the underlying property_spec begins at every
occurrence of the inferred clocking event.

 

Given the current clock inferring rules, I do not see a way to infer
clock from an always_comb. 

 

Thanks.

Manisha

 

 

 

 

From: Korchemny, Dmitry [mailto:dmitry.korchemny@intel.com] 
Sent: Wednesday, May 07, 2008 10:39 PM
To: Kulshrestha, Manisha
Cc: sv-sc@server.eda.org; sv-ac@eda.org
Subject: Concurrent assertions in always procedures

 

Hi Manisha,

 

In the yesterday's meeting you raised a question whether concurrent
assertions are legal in an always_comb procedure. Here is my
understanding:

 

It is written in the LRM (16.14.5 Embedding concurrent assertions in
procedural code):

 

A concurrent assertion statement can also be embedded in a procedural
block. For example:

property rule;

a ##1 b ##1 c;

endproperty

always @(posedge clk) begin

<statements>

assert property (rule);

end

If the statement appears in an always procedure, the property is always
monitored. If the statement appears

in an initial procedure, then the monitoring is performed only on the
first clock tick.

 

Note that always is written in New Times Roman, and not in courier,
which means that this is a generic name of all kinds of always
procedures, and not only of "always" proper.

 

Thanks,

Dmitry

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