VHDL Issue Number:      0031
Classification:         Language Definition Problem
Language Version:       VHDL-87
Summary:                Sensitivity of implicit processes is unclear.
Related Issues:         0204
Relevant LRM Sections:  9.5
Key Words and Phrases:  Primary, signal parameter
Current Status:         Superseded
1076-1993 Disposition:  Closed (All Issues Completely Addressed)
Disposition Rationale:  Section 9.5 (rule E) now refers to section 8.1 
                        which is a recursive declaration of how to construct
                        a sensitivity list.
Superseded By:          N/A
-----------------------
Date Submitted:         1989/02/10
Author of Submission:   Doug Dunlop
Author's Affiliation:   Intermetrics, Inc.
Author's Post Address:  4733 Bethesda Ave #415
                        Bethesda, MD  20814
Author's Phone Number:  (301) 657-3775
Author's Fax Number:    
Author's Net Address:   dunlop@inmet.inmet.com
-----------------------
Date Analyzed:          1991/03/21
Author of Analysis:     Alex Zamfirescu
Revision Number:        $Revision: 1.8 $
Date Last Revised:      $Date: 1995/05/13 21:53:48 $


Description of Problem
----------------------
Let S1 and S2 be signals and let F be a function that has a signal parameter.
Consider the concurrent signal assignment

     S1 <= F(S2);

Is S2 in the sensitivity set of the wait statement of the process derived from
the concurrent signal assignment?  One would expect this to be the case;
however, in this context, is S2 a primary?  If the intent is to apply the
production

              actual_designator ::= signal_name

for S2 (as would make sense since a signal name is required as the actual), it
would not be a primary and hence would not be included in the wait statement
sensitivity set.


Proposed Resolution
-------------------
Whether S2 in the above example is a primary or not is debatable but the intent
is clear.  S2 should be in the sensitivity list of the above process and will
be implemented it that way.


VASG-ISAC Analysis & Rationale
------------------------------
This issue is covered more fully in Issue Report 0204.


VASG-ISAC Recommendation for IEEE Std 1076-1987
-----------------------------------------------
See Issue Report 0204.


VASG-ISAC Recommendation for Future Revisions
---------------------------------------------
See Issue Report 0204.