VHDL Issue Number: 0067 Classification: Language Definition Problem Language Version: VHDL-87 Summary: Definition of locally static name not valid for alias indexed names. Related Issues: Relevant LRM Sections: 8.3 Key Words and Phrases: Alias, indexed name, locally static name Current Status: Analyzed 1076-1993 Disposition: Unknown Disposition Rationale: ?? Superseded By: N/A ----------------------- Date Submitted: 1989/02/10 Author of Submission: Doug Dunlop Author's Affiliation: Intermetrics, Inc. Author's Post Address: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: Clive R. Charlwood Revision Number: $Revision: 1.8 $ Date Last Revised: $Date: 1995/05/13 19:34:42 $ Description of Problem ---------------------- A locally static name is one where it can be determined at analysis time which object is being referenced. For example, in a signal assignment such as (A, B) <= ... A and B have to be locally static names so that at analysis time the check for duplication described in LRM 8.3 can be performed. Now if X is an alias of an array signal Y, a signal assignment such as (X(...), Y(...)) <= ... is legal but the above check cannot be performed because the subtypes (i.e., the bounds) of X and Y need not be locally static. Proposed Resolution ------------------- An indexed name whose prefix is an alias is not a locally static name, regardless of the class of the indexing expression. VASG-ISAC Analysis & Rationale ------------------------------ This is a reasonable interpretation. However, we are concerned that the LRM language will be difficult to craft. We have decided to leave this to the 92 language designers. VASG-ISAC Recommendation for IEEE Std 1076-1987 ----------------------------------------------- Assume that an indexed name whose prefix is an alias is never locally static. VASG-ISAC Recommendation for Future Revisions --------------------------------------------- Carefully reword the LRM to explicitly state that an indexed name whose prefix is an alias in never locally static.