RE: [sv-bc] Question on const declaration RHS

If you take this literally, this defines what it "can" have as RHS, not
what it "cannot" have. I agree with mantis 2372. This sentence should be
removed.

 

________________________________

From: Surya Pratik Saha [mailto:spsaha@cal.interrasystems.com] 
Sent: Tuesday, September 23, 2008 11:55 AM
To: Rich, Dave
Cc: sv-bc@eda.org
Subject: Re: [sv-bc] Question on const declaration RHS

 

Hi Dave,
Here is the 1800-2005 LRM text:
A static constant declared with the const keyword can be set to an
expression of literals, parameters, local parameters, genvars,
enumerated names, a constant function of these, or other constants.

This does not match with your statement.



Regards
Surya



-------- Original Message  --------
Subject: Re:[sv-bc] Question on const declaration RHS
From: Rich, Dave <Dave_Rich@mentor.com> <mailto:Dave_Rich@mentor.com> 
To: Surya Pratik Saha <spsaha@cal.interrasystems.com>
<mailto:spsaha@cal.interrasystems.com> , sv-bc@eda.org
Date: Tuesday, September 23, 2008 9:45:51 PM



Surya,
 
A "const" does not affect the RHS of the declaration. Whatever is
allowed for a non-cost variable declaration is allowed for a const. In
fact, a const variable declared inside an automatic block is initialized
every time the block is entered to whatever is the current value of the
RHS expression. It's just that a const variable becomes read-only after
initialization.
 
Dave
 
 
  

	-----Original Message-----
	From: owner-sv-bc@server.eda.org
[mailto:owner-sv-bc@server.eda.org]
	    

On
  

	Behalf Of Surya Pratik Saha
	Sent: Tuesday, September 23, 2008 12:45 AM
	To: sv-bc@server.eda.org
	Subject: [sv-bc] Question on const declaration RHS
	 
	Hi,
	As per SV 1800 LRM, the RHS side of 'const' declaration should
be
	consisting of normal const_expression or anything which is
already
	declared by another 'const' declaration.
	 
	But consider the e.g. below:
	module top;
	    int x;
	    function int f(input y);
	        x = 1;
	        return f + x;
	    endfunction
	    const int r1 = f(1); // function 'f' is not a constant as it
used
	    

a
  

	global non-parameter variable 'x'
	    const int r2 = x; // 'x' is not declared with 'const'
	endmodule
	 
	Most of the standard simulators pass the case. Is it a bug in
the
	simulators? Also OVM package has this type of declaration too
which is
	against LRM. Please comment.
	 
	--
	Regards
	Surya
	 
	 
	 
	 
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