Re: [sv-ac] mantis 1550

I agree with the clarified proposal. So,
I vote yes on 1550.

I think that this clarification should be reflected in the text.

Doron


Eduard Cerny wrote:

>That's what I had in mind and tried to explain.
>ed 
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>>-----Original Message-----
>>From: owner-sv-ac@eda.org [mailto:owner-sv-ac@eda.org] On 
>>Behalf Of Rich, Dave
>>Sent: Thursday, November 02, 2006 10:53 AM
>>To: john.havlicek@freescale.com; sv-ac@eda-stds.org
>>Subject: RE: [sv-ac] mantis 1550
>>
>>I think the semantics of the return value of these function is no
>>different then the simple Verilog system function $time. 
>>
>>You have to distinguish between the values returned by 
>>references to the
>>function versus evaluation events scheduled by a processes waiting on
>>the event expression. This is somewhat harder to put into 
>>words than to
>>actually implement it.
>>
>>I think it is OK to say that the value that will be returned by the
>>function is updated in the postponed region because no one 
>>can schedule
>>a call in that region. You can also say that an update event is
>>scheduled for the active region of the next time slot.
>>
>>Dave
>>
>>
>>    
>>
>>>-----Original Message-----
>>>From: owner-sv-ac@server.eda.org [mailto:owner-sv-ac@server.eda.org]
>>>      
>>>
>>On
>>    
>>
>>>Behalf Of John Havlicek
>>>Sent: Thursday, November 02, 2006 6:59 AM
>>>To: sv-ac@server.eda-stds.org
>>>Subject: [sv-ac] mantis 1550
>>>
>>>Hi Ed:
>>>
>>>In general, I like the semantics for $sampled and $past in your 1550
>>>proposal, but I have some concerns that make me vote "no" at this
>>>time.
>>>
>>>1. I don't think we have yet clarified when the return 
>>>      
>>>
>>values of these
>>    
>>
>>>   functions change.  You say that $sampled is stable throughout the
>>>   simulator timestep and that $past changes in the 
>>>      
>>>
>>postponed region.
>>    
>>
>>>   Can the return value of $past really change in the postponed
>>>      
>>>
>>region?
>>    
>>
>>>   I think it is bad if there can be calls/references to any of the
>>>   sampled value functions between the point that the return value
>>>   of one changes and the point that the return value of another
>>>   changes in the same timestep.
>>>
>>>2. A related question is that of the semantics of events that refer
>>>   to sampled value functions.  The intuition seems to be that the
>>>   return values of sampled value functions change "in between" the
>>>   simulation timesteps, so when do we schedule something like
>>>
>>>      @($sampled(p)) S1
>>>
>>>   when written in various contexts (e.g., in a module, in 
>>>      
>>>
>>a program)?
>>    
>>
>>>3. I would like to see $rose, $fell, and $stable defined in terms of
>>>   $sampled and $past.  I think this should be easy.
>>>
>>>We may need to get some SV-BC or other help with items 1 and 2.
>>>
>>>Best regards,
>>>
>>>John H.
>>>      
>>>
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>>
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