Subject: Re: [sv-ac] alternative proposal to "syn1": remove binary delay
From: John Havlicek (john.havlicek@motorola.com)
Date: Tue Feb 11 2003 - 23:03:35 PST
Adam and All:
Which is more vile? That "s ;([0]t)" is not the same as "s;[0]t",
or that "[1]t" is the same as "t"? Is this dilemma the price that
must be paid for a ";" with no argument?
A few comments interspersed below.
J.H.
> Hi Cindy;
>
>
> Here are some sequence examples that I would like to see if the
> current proposal works with them.
>
> Specifications:
> 1. A and 2 cycles later B
> 2. A and 1 or 2 cycles later B
> 3. A followed by seqC (seqC is C now or in 10 cycles.)
What does "followed by" mean?
* "A non-overlapping concatenated with seqC" is coded as "A ; seqC"
* "A overlapping concatenated with seqC" is coded as "A;[0] seqC".
> 4. A implies B (same cycle)
> 5. A implies B (in next cycle)
> 5. A implies B in the next 1 to 10 cycles.
>
>
> Alternative to syn1:
>
> 1. (A; [2] b) ok
> 2. (A; [1:2] b) ok
> 3. sequence seqC = ([1:10] c);
> (A; seq) missing A&C as legal.
Notice that in the original LRM, you would have coded
sequence seqC = ([0:9] c);
(A; seqC)
and you would have the same problem. You have to decide whether you want
(A; seqC)
or
(A;[0] seqC).
> 4. (A => B); ok
> 5. (A => [1] B) incorrect.
This is a coding mistake. If one adopts the new proposal, one must
understand that "[1]B" means "B", not "1;B". This is like learning
to count from 1 instead of from 0. My personal opinion is
that "[0]B" is more intuitive for "B" than "[1]B". However, this
leads right back to the problems with "s;([n]t)" vs "s;[n]t". It
seems a matter of taste which is the lesser evil.
> 6. (A => [1:10] B) missing cycle 10 since A => B is same cycle.
Same kind of coding mistake.
>
> These can be fixed by rewriting them as:
>
> 3 ???
> 5. (A => [2] B) though seems to say 2 cycles later
> 6. (A => [2:10] B) <same reasoning>
>
>
> LRM 0.79:
>
> 1. (A; [2] b) ok
> 2. (A; [1:2] b) ok
> 3. sequence seqC = ([0:10] c);
> (A; seq) ok.
I disagree. See above.
> 4. (A => b); ok
> 5. (A => [1] b); ok
> 6. (A => ([1:10] b) ok.
>
>
> Is this accurate? How would one rewrite #3 for alternative to syn1 ? Which is better?
>
>
> Adam Krolnik
> Verification Mgr.
> LSI Logic Corp.
> Plano TX. 75074
>
>
>
>
>
>
>
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