AtomicComposites < P1076/Ballots

P1076/Ballots Web>Vhdl2019CollectedRequirements>AtomicComposites (2020-02-17, JimLewis) (raw view)EditAttach
---+ Atomic Composite Signals

<br />%TOC%
---++ Recommendation: Investigate Further

---++ Proposal Information
   * Who Updates:
   * Date Last Updated
   * Priority:
   * Complexity:
   * Focus: Performance

---++ Requirement Summary & Rationale

[[http://www.eda-twiki.org/vhdl-200x/vhdl-200x-perf/proposals/perf05.txt"][Proposal here]]

IEEE 200X Performance Change Proposal

ID:	  PERF-05

Proposer:     John Ries
email:        johnr@model.com

Status:       Open
Proposed:     05-May-2003
Analyzed:     Date
Resolved:     Date

Enhancement Summary:     Signal Atomicity
Related issues:          PERF04
Relevant LRM section:    

Enhancement Detail:
----------------------------
Composite signals semantics are currently defined in terms 
of their scalar subelements. It has been requested to allow
users to control whether a composite signal is single indivisible
object, one signal per scalar subelement, or a signal per
composite subelement.


Analysis:
----------------------------
To be performed by the 200X Performance Working Group


Resolution:
----------------------------
To be performed by the 200X Performance Working Group]

---++ Arguments For

_Add your signature here to indicate your support for the proposal_

---++ Arguments Against

_Add your signature here to indicate your do not support for the proposal_

[[2013_MeetingJanuary31][From Jan 31, 2013 meeting]]
   * Normal composites track events on each subelement
   * Atomic composite only tracks events on the composite
   * With Atomic do I get element resolution functions or do require a resolution function for the entire composite?
   * Can simulators already do this?
      * To some degree. If elements not accessed
   * Are there use cases that the compiler needs help with?
      * What sort of help does the compiler need?
      * Will this provide any benefit?
   * Recommend Investigate Further

---++ General Comments
---+++ Email Reflector Comments

   * [[http://www.eda.org/vhdl-200x/vhdl-200x-perf/hm/][Original VHDL-200X Simulation Performance Reflector Archive]]

---++++ From: [[Main.PeterFlake][Peter Flake]] (Thu Jan 03 2013 - 09:48:21 PST)

Perf 5: Signal atomicity

I do not understand the effect of this enhancement, and its purpose.

---++++ From: [[Main.BrentHahoe][Brent Hayhoe]] (Mon Jan 21 2013 - 13:09:26 PST)

PERF-05 Signal Atomicity

I am guessing here, but could this be linked to this scenario: 
<sticky>
<pre>
<verbatim>
   type comp_rt is
     record
sig1_l : Std_Logic;
sig2_l : Std_Logic;
     end record comp_rt;
   signal rec_grp_rs : comp_rt;
...
begin
   process a1(rec_grp_rs.sig1_l)
.....
   process a2(rec_grp_rs.sig2_l)
</verbatim>
</pre></sticky>

In order to trigger each process independently, the selected record elements would each act as a sort of sub-signal for the sensitivity lists, rather than have the processes sensitive to the entire record signal.
Topic revision: r4 - 2020-02-17 - 15:34:49 - JimLewis
P1076/Ballots