Re: [sv-ec] Question Regrading the Open value range list with Covergroup bins

<forwarding bounced email from Saurabh Sharma>


-------- Original Message --------
Subject: Re: [sv-ec] Question Regrading the Open value range list with Covergroup bins
Date: Mon, 07 Apr 2008 13:58:23 +0530
From: Saurabh Sharma <saurabhs@cadence.com>
To: Steven Sharp <sharp@cadence.com>, sv-ec@eda.org
CC: Neil.Korpusik@Sun.COM, saurabhs@cadence.com
References: <200804042351.m34Npvw11059@quicksand.Cadence.COM>

Hi Steven,

Thanks for your comments. I complete agree with you.

The only issue why i bought this in to notice is that
the BNF may mislead users to create erroneous scenario as shown below

module example;
    logic clk;
    int tmp;

   covergroup cg2 @(posedge clk);
    ce: coverpoint var1 {
                bins  b = { [tmp : 100]
};
                 }
        endgroup :cg2

        cg2 cg2_inst = new;

endmodule

This  of course is against what is expected by the LRM.

Thanks
Saurabh Sharma


Steven Sharp wrote:

>>         " The open_range_list used to specify the set of values associated 
>>    
>>
>with
>  
>
>>           a bin shall be *constant* *expressions* (see 11.2.1), instance 
>>    
>>
>constants
>  
>
>>           (for classes only), or non-ref arguments to the coverage group."
>>
>>        But the  BNF is as shown below.
>>
>>       open_range_list ::= open_value_range { , open_value_range }
>>       open_value_range ::= value_range
>>       value_range ::= expression | [ expression : expression ]
>>
>>      I feel that here it should be "constant_expression" and not "expression"
>>      and should be corrected.
>>    
>>
>
>If the BNF only allowed constant_expressions, then the language would
>only allow constant expressions.  But from the text you quoted, it allows
>instance constants for classes, and non-ref arguments to the coverage group.
>To allow these, the BNF must allow them.
>
>It might be possible to restrict this a little more with the BNF, but it
>is simpler to use the general production and restrict it with the semantic
>rules you quoted.
>
>Steven Sharp
>sharp@cadence.com
>
>  
>


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