RE: [sv-ac] RE: Call to vote: Due March 2 (resend, typo fix)

Hi,
 
I would like to keep the example as it is to make it clear that padding does apply in this case. It will be good to explain why bit '0' is also getting included in the count.
 
Thanks.
Manisha

________________________________

From: owner-sv-ac@eda.org [mailto:owner-sv-ac@eda.org] On Behalf Of ben cohen
Sent: Friday, February 25, 2011 11:35 PM
To: Little Scott-B11206
Cc: Korchemny, Dmitry; sv-ac@eda.org
Subject: Re: [sv-ac] RE: Call to vote: Due March 2 (resend, typo fix)

Scott,
Your suggestion is OK with me. It general, it is a better methodology to fully specify the bits. However, the padding rule applies for literal constants when the size of the unsigned number is smaller than the size specified for the literal constant. If this is something we want to clarify, then the 2'b1 example should be explained. It's up to us to determine what we want to describe.
Ben

On Fri, Feb 25, 2011 at 9:51 AM, Little Scott-B11206 <B11206@freescale.com> wrote:

        Hi Ben:

        I don’t think we need to use or reference the rules about how to handle unspecified bits. That isn’t the purpose of the section or example. We should keep things simple and write 2’10. It is only one more character.

        Thanks,

        Scott

        From: ben cohen [mailto:hdlcohen@gmail.com]
        Sent: Friday, February 25, 2011 11:47 AM
        To: Little Scott-B11206
        Cc: Korchemny, Dmitry; sv-ac@eda.org
        Subject: Re: [sv-ac] RE: Call to vote: Due March 2 (resend, typo fix)

        We could make a reference to section 5.7.1 Integer literal constants

        That states: "If the size of the unsigned number is smaller than the size specified for the literal constant, the unsigned number shall be padded to the left with zeros. If the leftmost bit in the unsigned number is an x or a z, then an x or a z shall be used to pad to the left, respectively. If the size of the unsigned number is larger than the size specified for the literal constant, the unsigned number shall be truncated from the left."

        Thus, - $countbits (expression, 2’b1) returns the number of bits in expression having values 1 or 0.

        Per 5.7.1, this is equivalent to $countbits (expression, 2’b01)

        Ben Cohen

        On Fri, Feb 25, 2011 at 9:24 AM, Little Scott-B11206 <B11206@freescale.com> wrote:

        Mantis 2476 __X__ Yes ____ No

        http://www.verilog.org/mantis/view.php?id=2476

        http://www.eda-stds.org/mantis/file_download.php?file_id=4816&type=bug

        Assuming that the following small issues are handled.

        Is the statement:

        - $countbits (expression, 2’b1) returns the number of bits in expression having values 1 or 0.

        I believe it is more clear if it reads 2’b10.

        $isunknown is also provided for convenience and backward compatibility. Why is not introduced and the equivalence defined with the rest of those functions?

        In the first part of the proposal the Sampled Value System Functions is listed as section 20.13 and then in the last section it is listed as 20.14. I think it would be best to be consistent within the proposal. Either assume the new section has been inserted or assume it is has not. I am not sure which is best.

        Mantis 2804 __X__ Yes ____ No

        http://www.eda-stds.org/svdb/view.php?id=2804

        http://www.eda-stds.org/mantis/file_download.php?file_id=4814&type=bug

        
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