Minutes from SV-AC Meeting
Date: 2010-11-09
Time: 16:00 UTC (9:00 PDT)
Duration: 1.5 hours
Dial-in information:
Meeting ID: 38198
Phone Number(s):
1-888-813-5316 Toll Free within North America
Live Meeting:
https://webjoin.intel.com/?passcode=2598352
Agenda:
- Reminder of IEEE patent policy.
See:
http://standards.ieee.org/board/pat/pat-slideset.ppt
- Minutes approval
- Email ballot results
None
- New issues
None
- Enhancement progress update
Simulation semantics of deferred assertions
Continuous and blocking assignments in checkers
- Issue resolution/discussion
2206: Random simulation of non-deterministic free variables in checkers
- Opens
SV-AC meeting schedule
Attendance Record:
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
Attendance re-initialized on 2010-07-06:
v[xxxxxx-x-xxxxx--xxx] Laurence Bisht (Intel)
v[xxxx-xxxxxxxxxxxxx-] Eduard Cerny (Synopsys)
v[xxxxxx-xxxxx-xxxxxx] Ben Cohen
v[xx-x-xxx-x--xxxxxxx] Surrendra Dudani (Synopsys)
v[-xx---xxxx---x-xxxx] Dana Fisman (Synopsys)
v[xxx-xxxx-x-xxxxxxxx] John Havlicek (Freescale)
v[xx-xxx-xxxxxxxxxxxx] Tapan Kapoor (Cadence)
t[xx--xxxxxxxxxxxxxxx] Dmitry Korchemny (Intel ¿ Chair)
v[xx--xxxxxx-xxxxxxxx] Scott Little (Freescale)
v[x-xxxxxxxxx-xxxxxxx] Manisha Kulshrestha (Mentor Graphics)
v[xxxxxxxxxxxxxxxxxxx] Anupam Prabhakar (Mentor Graphics)
v[xxx-xx--xxxxxxx-xxx] Erik Seligman (Intel)
v[xx--xxxxxx-xxxxxxx.] Samik Sengupta (Synopsys)
v[x-xxxxxxxxxxxxx-xxx] Tom Thatcher (Oracle ¿ Co-Chair)
|- attendance on 2010-11-09
|--- voting eligibility on 2010-11-09
Minutes:
- Reminder of IEEE patent policy.
See:
http://standards.ieee.org/board/pat/pat-slideset.ppt
- Minutes approval
Erik: Move to approve minutes
John: Second
Vote results 12y, 0n, 0a
- Opens
SV-AC Meeting schedule:
Manisha: Can we change the meeting to 8:30
Because US is now on standard time, her local time is 1 hour later.
Tom: 8:00 would be too early, 8:30 is doable.
Erik: Move to reschedule meeting 1/2 hour ealier
John Second
vote results; 136, 0n, 0a
Ed: Will reschedule phone conference
Dmitry: Will reschedule livemeeting.
- Issue resolution/discussion
2206: Random simulation of non-deterministic free variables in checkers
Dmitry: AC had voted to close as duplicate
Champions had opposed: "Duplicate of what"
Erik: 17.7.2 seems to describe this operation
John: Move to Change status to "no change required"
Include a reference to 17.7.2
Erik: Second
Vote results: 12y, 0n, 0a
(Dana Joined)
- Enhancement progress update
Simulation semantics of deferred assertions:
Discussing 3206 example
Deferred assertion embedded in an always_ff @(posedge clk)
References variables a & c
C is driven from a non-blocking assignment in the same block
a is driven from a program block through a clocking block with #0
sampling.
Tom: Seems that this example: assert #0 could be replaced by assert
property with no loss of function.
Dmitry: Not for equivalence checking. Concurrent assertions require a clock
Formal equivalence checking does not define a clock.
John: But this means that assertion is checked all the time.
John: Is it typical to write assertion on both primary input and internal
signals? Would prefer to see assertion written only on primary inputs.
Continuous assignments in checkers:
Dmitry: In his paper, he proposed that continuous assignments would update
in reactive region.
Anupam: Does it make sense to synchronize checker inputs in reactive region
Like clocking block: Any input to the clocking block is only seen
in the observed region.
If checker inputs were synchronized similarly, then deferred
assertions within checkers would not glitch.
Ed: Random variables: Assigned new values just before observed region
Shouldn't continuous assignments be similar?
Ed: Given example assertions in
LiveMeeting
(note: We should post the examples on the e-mail reflector)
If continuous assignments occur in Reactive, then A1 would be bad
If occurs in Active, then A2 would be bad.
Dmitry: But if we use Anupam's suggestion of clocking-blok synchronization,
that would fix A1.
Tom: Isn't this the same as just having sampled values for inputs?
Anupam: No, it's different.
Lawrence: This would break the rewriting algorithm.
Ed: This would break symmetry between active & reactive
Dmitry: One other suggestion would be adding Re-observed region.
Manisha: We can't move the regions. We can only describe how checkers work
with the given regions.
Dmitry will ask working group about this at next working group meeting.
Dmitry: Three approaches
New Re-Observed region
Move observed region after reactive
Handle a mix of design and test bench variable correctly
Sampled Value Definition
Dmitry: Anupam had suggested moving definitions of sampled value to the
section on the $sampled function.
Samik: Why is this a big change? It seems to be just copying one section
to another place tin the LRM.
John: Think it's better to put the definition before, and have the $sampled
section refer to it.
Meeting adjourned.