VHDL Issue Number:      1123
Classification:         Language Definition Problem
Language Version:       VHDL-93
Summary:                Simulation cycle does not account for processes
			resuming after expiration of the timeout interval
Related Issues:         <Xref all related issues by number.>
Relevant LRM Sections:  12.6.4, 8.1
Key Words and Phrases:  Process resumption, timeout interval
Current Status:         Submitted
1076-1993 Disposition:  <One of the following, assigned by ISAC:>
                        Unknown
                        Closed (All Issues Completely Addressed)
                        Bugs Fixed, Enhancements Outstanding (No ISAC Issues)
                        Superseded (ISAC Issues Outstanding)
Disposition Rationale:  <Explain rationale for 1993 disposition.  Succinct.>
Superseded By:          N/A
-----------------------
Date Submitted:         13 August 1996
Author of Submission:   Ernst Christen
Author's Affiliation:   Analogy, Inc.
Author's Post Address:  9205 SW Gemini Drive
                        Beaverton, OR 97008
Author's Phone Number:  (503) 520-2720
Author's Fax Number:    (503) 643-3361
Author's Net Address:   christen@analogy.com
-----------------------
Date Analyzed:          TBD <Enter date analyzed in dd month year form.>
Author of Analysis:     TBD <Enter author of analysis.>
Revision Number:        1 <To be incremented by the ISAC.>
Date Last Revised:      13 August 1996


Description of Problem
----------------------
The LRM states at 8.1-71 that "The suspended process will resume, at the
latest, immediately after the timeout interval has expired." 

In section 12.6.4 there is only one place in the simulation cycle where
processes resume: step d at 12.6.4-650. This step only addresses those
processes that resume due to events on signals to which they are sensitive.
Processes resuming as a result of their timeout interval expiring are
only considered for the purpose of finding Tn (step f.3 at 12.6.4-657). 
The definition of the simulation cycle does therefore not include the
information where and when a process resumes whose timeout interval has 
expired.


Proposed Resolution
-------------------
Add to step d) of the simulation cycle processes that resume after their 
timeout interval has expired, for example:

d) ... then P resumes.  For each process P, if its timeout interval has
expired in this simulation cycle, then P resumes.


VASG-ISAC Analysis & Rationale
------------------------------
TBD


VASG-ISAC Recommendation for IEEE Std 1076-1993
-----------------------------------------------
TBD


VASG-ISAC Recommendation for Future Revisions
---------------------------------------------
TBD