[sv-ac] RE: Comments on proposal for 1668

Hi John,

I agree with your comments. Why I suggested to use clock tick (whether
we define it more precisely in 16.1 or not) is because it is used a lot
thorughout th document and it is simpler than using "occurrence... ". 
I will have a look at the new version later today.

Bestest..
ed

> -----Original Message-----
> From: John Havlicek [mailto:john.havlicek@freescale.com] 
> Sent: Saturday, July 21, 2007 1:17 PM
> To: Eduard.Cerny@synopsys.COM
> Cc: john.havlicek@freescale.com; sv-ac@eda-stds.org
> Subject: Re: Comments on proposal for 1668
> 
> Hi Ed:
> 
> I have updated the proposal, and I think I have addressed
> all of your comments.  The new proposal is on Mantis and attached.
> 
> See also the remarks below.
> 
> J.H.
> 
> > Hello John,
> > 
> > I have looked at the proposal (not yet the formal 
> semantics) for Local
> > Variable Initializers. It looks good. Please see some minor comments
> > below.
> > 
> > Best regards,
> > ed
> > -------------
> > 
> > pp1, par.1: "be performed in order at" --> "be performed in 
> the order of
> > declaration at"
> > 
> 
> Done, although this does not affect the text changes to the LRM.
> 
> > pp1, par.2: "For properties, our formal semantics" --> "For 
> properties,
> > the current formal semantics"
> > Also, should it mention more explicitly that it is an error when the
> > sequence admits an empty match?=20
> 
> Done, although this does not affect the text changes to the LRM.
> 
> > 
> > pp3, after Syntax 16-12: Should it mention the kind of 
> types that are
> > allowed (or forbidden like for assertions) to be used with local
> > variable declarations? I have had quite a few inquiries about that.
> 
> Done.  I said that the types allowed are the same as those allowed
> in 16.5.1.  As a separate matter, we could consider relaxing 16.5.1.
> For example, I guess that bounded queues could be allowed.  Probably
> other things could be allowed too.
> 
> > 
> > pp5, longer par. before 16.9, p.336 CHANGE: "a local variable that s
> > assigned shall later become" --> "a local variable that s 
> assigned may
> > later become". I think that "shall" should only be used in 
> the specific
> > case that is stated in the next sequence.
> 
> I considered this carefully.  The entry phrase "Under certain
> circumstances" limits the scope of the "shall" to those circumstances,
> even though they have not yet been defined.  I don't think "may" is
> the right word because we are saying that the variables are required,
> not permitted, to become unassigned under the particular
> circumstances.
> 
> In the end, I changed the sentence to use neither "shall" nor "may":
> 
>   Under certain circumstances, a local variable that is assigned later
>   becomes unassigned.
> 
> Is this acceptable?
> 
> > 
> > pp6, count_a_cycles: formatting perhaps split the sequence 
> expression
> > over two lines.
> 
> Done.
> 
> > 
> > pp8, 16.13.7 1st 2 paragraphs: Why is it necessary to introduce the
> > notion of time step and then relate it to the clocking 
> event occurrence.
> > I think that it could be stated more simply using "clock 
> tick" which is
> > defined in 16.4.
> 
> I have changed the text to use "clock tick" or "tick of the clock" 
> rather than "occurrence of the clocking event" in these two 
> paragraphs.
> I think the wording is simpler than what I had before.
> 
> I think that 16.4 is actually defective in introducing "clock 
> tick" as 
> an apparently new basic concept rather than defining it in terms of 
> other SystemVerilog concepts.  We could fix this in a separate Mantis
> item.
> 
> To my mind, any "clock" that can have a "tick" in the sense of
> Clause 16 is associated with a "clocking event" that can "occur", and
> there is no difference between a "clock tick" and an "occurrence of
> the clocking event".
> 
> > 
> > pp8, last par.: "preponed value" --> "sampled value"
> 
> Done.
> 
> > 
> > last page, before A.2.10: Would it be useful to also give 
> the equivalent
> > formulation that does not use the initialization at 
> declaration in this
> > example? I.e., use the ##0?
> > ------------
> > 
> 
> Done, although I use |-> rather than ##0 to match the function push
> in the formal semenatics document.
> 
> 

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