( ESNUG 450 Item 6 ) --------------------------------------------- [01/25/06]

From: Daniel Lima Ferrao <dlferrao=usr domain=inf.ufrgs.br>
Subject: How to force PrimeTime to produce a Multiple-Input Change Vector?

Hi John,

I have found some strange behaviour with the "True-delay Input Vector"
generated by the report_timing -true option in PrimeTime (Ver W-2004.12).

When applying the vector reported with the set_case_analysis command, that
vector can't sensitize the critical path reported as true, and another path
is reported (with smaller delay).

The problem is that the vector reported is a "single-input change" vector.
Actually I've never got a vector that have multiple-input changes.

So the -true algorithm uses a vector to sensitize that is different from
the vector reported?  The vector reported is like this one:

     True-delay Input Vector
     -------------------------------------------
     a[0] (in)                            1
     a[1] (in)                            1
     b[0] (in)                            f
     b[1] (in)                            0
     cin (in)                             1

So I gotta a script that produces this commands:

     set_case_analysis 0 a[0]
     set_case_analysis 0 a[1]
     set_case_analysis 1 b[0]
     set_case_analysis 1 b[1]
     set_case_analysis fall cin

But this vector can't sensitize the path reported, to do so the right vector
must be:

     set_case_analysis fall a[0]
     set_case_analysis fall a[1]
     set_case_analysis 0 b[0]
     set_case_analysis 0 b[1]
     set_case_analysis fall cin

That is a multiple-input change vector.

Is there a way to force PrimeTime to produce a multiple-input change vector
or are only single-input change vectors supported??

    - Daniel Lima Ferrao
      UFRGS                                      Rio Grande Do Sul, Brazil