RE: [sv-bc] e-mail ballot due Monday, Feb 18, 8AM PST

Ah yes, I wasn't thinking of scheduling semantics and focused in on just
that one process.  Okay, I'll make it "could be" and upload the proposal
again.

-Tom

>-----Original Message-----
>From: owner-sv-bc@server.eda.org [mailto:owner-sv-bc@server.eda.org] On
>Behalf Of Gordon Vreugdenhil
>Sent: Friday, February 15, 2008 10:08 AM
>To: Alsop, Thomas R
>Cc: Maidment, Matthew R; sv-bc@server.eda.org
>Subject: Re: [sv-bc] e-mail ballot due Monday, Feb 18, 8AM PST
>
>
>
>Alsop, Thomas R wrote:
>> Okay, how does this look?
>>
>
>Mostly Ok -- see below.
>
>
>>
>> *always_comb begin : *a1
>>
>>     *unique* *case* (1'b1)
>>
>>        a     : z = b;
>>
>>        not_a : z = c;
>>
>>     *endcase *
>>
>> *end*
>>
>>
>>
>> In this example the unique-case is checking for overlap in the two
>> case-item selects.  When a and not_a are in state 0 and 1
respectively
>> and a transitions to 1, this unique-case will be executed while a and
>                                            ^^^^^^^
>
>Nope -- "could be" is correct here; "will be" is not.  When "a"
transitions
>to 1 there is no guarantee about the relative scheduling so only
>"could be" is correct.
>
>> not_a are both true, so the violation check for uniqueness will fail.
>
>
>I would write this as:
>
>   When a and not_a are in state 0 and 1 respectively and a transitions
to
>1,
>   this unique-case could be executed with a and not_a both being 1.
>   If that occurs, the violation check for uniqueness will fail, but
>   since this violation check is in the active region set the failure
>   is not reported immediately.  After the update to not_a, process a1
will
>   be rescheduled, which results in a flush of the original error.
After
>   that, the violation check will pass, and no error will be reported.
>
>
>Gord
>
>
>--
>--------------------------------------------------------------------
>Gordon Vreugdenhil                                503-685-0808
>Model Technology (Mentor Graphics)                gordonv@model.com
>
>
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