RE: [sv-ac] call to vote on 1682

From: Korchemny, Dmitry <dmitry.korchemny_at_.....>
Date: Mon Nov 05 2007 - 06:11:02 PST
Also are mine.

 

Thanks,

Dmitry

 

-----Original Message-----
From: Kulshrestha, Manisha [mailto:Manisha_Kulshrestha@mentor.com] 
Sent: Thursday, November 01, 2007 6:45 PM
To: Korchemny, Dmitry; john.havlicek@freescale.com; sv-ac@server.eda.org
Subject: RE: [sv-ac] call to vote on 1682

 

Hi,

 

My comments are included:

 

Manisha

 

-----Original Message-----

From: Korchemny, Dmitry [mailto:dmitry.korchemny@intel.com] 

Sent: Tuesday, October 30, 2007 7:45 PM

To: Kulshrestha, Manisha; john.havlicek@freescale.com;

sv-ac@server.eda.org

Subject: RE: [sv-ac] call to vote on 1682

 

Hi Manisha,

 

Please, see my comments below. I've uploaded a version with fixes and

also am attaching it here.

 

Thanks,

Dmitry

 

-----Original Message-----

From: owner-sv-ac@server.eda.org [mailto:owner-sv-ac@server.eda.org] On

Behalf Of Kulshrestha, Manisha

Sent: Tuesday, October 30, 2007 8:54 AM

To: john.havlicek@freescale.com; sv-ac@server.eda.org

Subject: RE: [sv-ac] call to vote on 1682

 

Hi,

 

I vote 'no' with the following comments.

 

1. The proposal says: "$steady_gclk(expression) returns true if the

sampled value of the expressions does not change at the next global

clock tick. Otherwise it returns false."

 

I think it should have same type of wording as $falling_gclk has (i.e.

if the sampled value of the LSB of the expression ....)

 

[Korchemny, Dmitry] I don't think so. Its definition should be

consistent with $stable, and the definition of $stable explicitly says:

" $stable returns true if the value of the expression did not change.

Otherwise, it returns false."

 

MK> OK. I checked the definition of $stable and this is fine.

 

2. The proposal says: "The use of these functions is limited to

assertion features only. It shall be an error to invoke these functions

outside of property expressions, this also implies that they shall not

be used in assertion action blocks."

Is 'assertion features' defined any where ? I believe these functions

can be used in sequences. Because the second sentence says that these

can not be used outside of property expressions. May be the sentence

should be something like " These functions shall be used only in the

concurrent assertion boolean expressions".

 

[Korchemny, Dmitry] I rewrote this paragraph as:

 

"It shall be an error to invoke the global clocking sampled value

functions outside of property expressions, this also implies that they

shall not be used in assertion action blocks."

 

MK> I am assuming that you mean that these global clocking sampled value

functions can be used only in property_expr. Somehow the term property

expressions is being used in the LRM to imply assertions also. E.g.

4.4.2.6 has "The code specified by blocking assignments in the program

block and the pass/fail code from property expressions are scheduled in

the Reactive region. The Reactive region is the reactive region set dual

of the Active region (see 4.4.2.2)." 

 

Also, are these functions allowed in sequences expressions ?

 

[Korchemny, Dmitry] I believe that the usage of "property expression" in
4.4.2.6 is wrong and should be fixed. In other cases property expression
and property_expr are used interchangeably.

 

I rewrote the above statement as: "The global clocking sampled value
functions may be invoked only in property_expr or in sequence_expr; this
implies that they shall not be used in assertion action blocks."

 

3. It says: "Additional restrictions are imposed on the usage of the

global clocking future sampled value functions: they shall not be nested

and they shall not be used in assertions containing sequence match items

(see 16.9, 16.10)." 

 

So, these restrictions are only for future sampled value functions. Not

for past ones. How would a nested $past() work ? Either way it needs

more clarity.

 

[Korchemny, Dmitry] I don't think we should provide more explanations

for the past value functions here, since regular $past functions can be

nested. If you think that the definition of the nesting of the regular

$past functions is not clear enough, it should be a subject of a

separate mantis.

 

4. It says "An evaluation attempt of an assertion containing global

clocking future sampled value functions ends at the global clocking tick

that follows the assertion clock tick at which the final boolean

expression of the assertion is evaluated,".

 

I think there should be a '.' instead of ',' at the end of this

statement.

[Korchemny, Dmitry] Fixed.

 

 Also it kind of implies that all the attempts of a assertion containing

future sampled value function will end at the next global clock tick.

This may not be the case if the last Boolean expression (which caused

failure or pass) does not contain future sampled value function. 

 

[Korchemny, Dmitry] I think that this will be difficult to define and

implement. It is also easier to the user when the definition is simple.

 

In the same paragraph it is using ":", is that according to the standard

? I am not sure.

 

[Korchemny, Dmitry] Why is it forbidden to use a colon in the LRM? Could

you be more specific?

 

MK> Here is the original sentence:

Note however, that the behavior of the disable iff clause and other

asynchronous assertion related controls (e.g.

$assertkill, see 19.10) remains consistent with its behavior for

assertions without global clocking

future sampled value functions (see 16.12): the completion of the

property evaluation does not include (or is

not contingent on) the additional global clocking tick.

 

MK> You just sent out email that you plan to remove the statements about

evaluation attempt. I am just wondering if this proposal needs to

clarify anything about disable iff or $assertkill. If the proposal does

not say anything then it implies that the behavior of these things is

not changing with the introduction of these new functions. What do you

think ?

[Korchemny, Dmitry] I removed the previous paragraph and added the
following text. This behavior also follows from the description of the
formal semantics. I will appreciate if you could suggest a better
formulation.

For assertions containing global clocking future sampled value functions
the behavior of the disable iff clause and other asynchronous assertion
related controls (e.g. $assertkill, see 19.10) remains consistent with
its behavior for assertions without global clocking future sampled value
functions (see 16.12).

Example 3.

Assume that the signal rst is high between times 82 and 84, and is low
at all other time moments. Then the following assertion

a3: assert property (@$global_clock disable iff (rst)
$changing_gclk(sig) 
                                     |-> $falling_gclk(clk))
   else $error("sig is not stable");

fails at time 80 (see Figure 16-14 Note to the editor: please, adjust
the reference), since rst was inactive between times 70 and 80.

 

Thanks.

Manisha

 

-----Original Message-----

From: owner-sv-ac@server.eda.org [mailto:owner-sv-ac@server.eda.org] On

Behalf Of John Havlicek

Sent: Wednesday, October 24, 2007 6:21 AM

To: sv-ac@server.eda.org

Subject: [sv-ac] call to vote on 1682

 

Hi Folks:

 

As we agreed in today's meeting, I am calling for a vote on 1682.

 

The documents are

 

  GlobalClockPastNextValueFunctions1682\ 071016_dk.doc

  GlobalClockPastNextValueFunctions1682\ 071016_dk.pdf

 

on Mantis.  These two should be identical from a technical perspective.

 

Please vote if you are eligible.  See the details below.

 

J.H.

 

------------------------------------------------------------------------

----------------

Ballot on Mantis 1682

 

- Called on 2007-10-23, final ballots due at 2007-10-30 T 23:59-07:00.

 

 v[xxxxxxxxxxx-xxxxxxxxxxxxxxxxxxxxxxxx-xx] Doron Bustan (Intel)

 v[xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx-x] Eduard Cerny (Synopsys)     

 n[------------x-xxx---------x-x-xxx-x---x] Surrendra Dudani (Synopsys)

v[xxxxx-xxxxxxxxx-xx-xxxxx-xxx-xxx-------] Yaniv Fais (Freescale)

t[xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx] John Havlicek (Freescale -

Chair)

 v[xxxxxxxxxxxxxxxxxxxxxrxxxxxxxxxxxxx-xxx] Dmitry Korchemny (Intel -

Co-Chair)

 v[xxxxx-xxx-x--xx--xxxxx----------xx-xxxx] Manisha Kulshrestha (Mentor

Graphics)

 n[--------------------xxxxx-------x-xx-x-] Jiang Long (Mentor Graphics)

n[------------x--xxx.....................] Joseph Lu (Altera)

v[xxxxxxxxx..............................] Johan Martensson (Jasper)

n[-----------------x--x-xx--xx-xxxxxxx-x-] Hillel Miller (Freescale)

v[-xxxxxxxxxxxxxxxxxxx-xxxxxxxx-xxxxxxxxx] Lisa Piper (Cadence)

v[-xx-xxxxxxx-x-xxxxx-x..................] Erik Seligman (Intel)

n[----x--------xxxx-----xxxx-xx----------] Tej Singh (Mentor Graphics)

v[xxxxx--xxxxxxxx-xxxxxxxxxxxxxxxxxxxxxxx] Bassam Tabbara (Synopsys)

v[xxxxxxxxxxxxx-xxxxxxxxxx...............] Tom Thatcher (Sun

Microsystems)

   |--------------------------------------- attendance on 2007-10-23

 |----------------------------------------- voting eligibility for this

ballot

|------------------------------------------ email ballots received

 

      Legend:

            x = attended

            - = missed

            r = represented

            . = not yet a member

            v = valid voter (2 out of last 3 or 3/4 overall)

            n = not valid voter

                t = chair eligible to vote only to make or break a tie

 

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Received on Mon Nov 5 06:12:40 2007

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