[sv-ac] RE: call to vote on 1900

Hi Manisha,

Please, see my comments below.

Thanks,
Dmitry

-----Original Message-----
From: Kulshrestha, Manisha [mailto:Manisha_Kulshrestha@mentor.com] 
Sent: Monday, January 07, 2008 8:26 PM
To: john.havlicek@freescale.com; sv-ac@eda.org
Cc: Bustan, Doron; eduard.cerny@synopsys.com; yaniv.fais@freescale.com;
Korchemny, Dmitry; johan.martensson@jasper-da.com; piper@cadence.com;
Seligman, Erik; bassam.tabbara@synopsys.com; thomas.thatcher@sun.com
Subject: RE: call to vote on 1900

Hi Dimitry,

The sequence methods are allowed in continuous assignments to checker
variables. But this contradicts with the language in section 16.13.6,
where it says the following:


The ended status of the sequence is set in the Observe region and
persists
through the Observe region. This method shall only be used to detect the
end point of a sequence used
in another sequence.

The triggered status of the sequence is set in the Observe region and
persists through the remainder of the time step. This method shall only
be used in wait statements or boolean
expressions (see 9.4.4) outside of sequence context or in the disable
iff boolean expression for
properties.

[Korchemny, Dmitry] I don't see any contradiction with the subclause
16.13.8 here since the assignments to checker variables are performed in
the Observed region.

Dimitry, I think we discussed this in one of the last meetings and
decided that the example and the language needs some fixing ? Since so
far 'matched' was not allowed out of sequences, some clarification is
needed how it will work in sequential and continuous assignments. How
the clock synchronization will happen ?

[Korchemny, Dmitry] There are some explanations in the text. The
fragment describing sequence methods (including 'matched') currently
reads (page 16):
***
The right-hand side of a checker variable assignment may contain
sequence methods ended and triggered (see 16.8.10), which can be used in
this case interchangeably, and the sequence method matched. The matched
method has its usual meaning in nonblocking assignments, and has the
same effect as ended and triggered in continuous assignments. For
example:

// a, b, c, d, clk1 and clk2 are bit variables defined elsewhere
sequence s1;
	@clk1 c ##[0:$] d;
endsequence : s1
sequence s2;
	@clk2 c ##[0:$] d;
endsequence : s1

checkvar bit x, y = 1'b0, z = 1'b0, u = 1'b0;
assign x = a && b;
always_check @clk1 begin
	y <= x && s1.ended;
	// y <= x && s.triggered; has the same meaning

	z <= s2.matched;
	u <= s2.ended;
end
Suppose that the sequence s2 has a match at time 80 and the nearest tick
of clk1 happens at time 90. Then at time 90 z will be assigned the value
1'b1 since match stores the result of s2 match until the arrival of the
first clk1 tick after the match (see 16.13.5). On the contrary, the
value of u at time 90 will be 0 since there is no match of s2 at time
90.
***

Could you send your suggestion how to clarify the text?

Thanks.
Manisha

-----Original Message-----
From: John Havlicek [mailto:john.havlicek@freescale.com] 
Sent: Monday, December 31, 2007 10:28 PM
To: sv-ac@eda.org
Cc: doron.bustan@intel.com; eduard.cerny@synopsys.com;
yaniv.fais@freescale.com; john.havlicek@freescale.com;
dmitry.korchemny@intel.com; Kulshrestha, Manisha;
johan.martensson@jasper-da.com; piper@cadence.com;
erik.seligman@intel.com; bassam.tabbara@synopsys.com;
thomas.thatcher@sun.com
Subject: call to vote on 1900

Hi Folks:

Since my last call to vote on 1900 did not reach the reflector,
I am calling for a new, 1-week vote.  This is that call.

I have copied the eligible voters individually because the 
reflector seems unreliable.

Please send your ballot both to the reflector and to me 
individually.

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

J.H.

------------------------------------------------------------------------
----------
Ballot on Mantis 1900

- Called on 2007-12-31, final ballots due by 2008-01-07 T 23:59-08:00.

 v[xxxxxxxxxxxxxxxxxxx-xxxxxxxxxxxxxxxxxxxxxxxx-xx] Doron Bustan (Intel)
 v[xxx--xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx-x] Eduard Cerny
(Synopsys)     
 n[--------------------x-xxx---------x-x-xxx-x---x] Surrendra Dudani
(Synopsys)
 v[xxxxxx-xxxxxx-xxxxxxxxx-xx-xxxxx-xxx-xxx-------] Yaniv Fais
(Freescale)
 t[xx--xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx] John Havlicek
(Freescale - Chair)
 v[xxxxxxxxxxxxxxxxxxxxxxxxxxxxxrxxxxxxxxxxxxx-xxx] Dmitry Korchemny
(Intel - Co-Chair)
 v[xxx-xxxxxxxxx-xxx-x--xx--xxxxx----------xx-xxxx] Manisha Kulshrestha
(Mentor Graphics)
 n[----------------------------xxxxx-------x-xx-x-] Jiang Long (Mentor
Graphics)
 n[-------x------------x--xxx.....................] Joseph Lu (Altera)
 v[xxxxxxxxxxxxxxxxx..............................] Johan Martensson
(Jasper)
 n[-------------------------x--x-xx--xx-xxxxxxx-x-] Hillel Miller
(Freescale)
 v[xxx-xxxx-xxxxxxxxxxxxxxxxxxx-xxxxxxxx-xxxxxxxxx] Lisa Piper (Cadence)
 v[xxxx-x-x-xx-xxxxxxx-x-xxxxx-x..................] Erik Seligman
(Intel)
 n[-----x-x----x--------xxxx-----xxxx-xx----------] Tej Singh (Mentor
Graphics)
 v[xxxx-x-xxxxxx--xxxxxxxx-xxxxxxxxxxxxxxxxxxxxxxx] Bassam Tabbara
(Synopsys)
 v[xxxxxxx-xxxxxxxxxxxxx-xxxxxxxxxx...............] Tom Thatcher (Sun
Microsystems)
   |----------------------------------------------- attendance on
2007-12-18
 |------------------------------------------------- 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 a valid voter
                t = chair eligible to vote only to make or break a tie
---------------------------------------------------------------------
Intel Israel (74) Limited

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