AdditionToAllKeywordInSensitivityLists < P1076

P1076 Web>Vhdl2019CollectedRequirements>AdditionToAllKeywordInSensitivityLists (2020-02-17, JimLewis) (raw view)EditAttach

---+ Process ALL and Implicit Signals

%TOC%

---++ Proposal Editing Information
   * Who Updates: [[Main.BrentHahoe][Brent Hayhoe]]
   * Date Proposed: 2014-05-30
   * Date Last Updated:
   * Priority:
   * Complexity:
   * Focus:

---++ Requirement Summary

The ability to include implicit signals in sensitiviy lists when using the keyword *ALL*.

Examples of such signals are those generated by the predefined attributes; *S'DELAYED(t)*; *S'STABLE(t)*; *S'QUIET(t)*; *S'TRANSACTION*.

---++ Related Issues:

---++ Proposal

---+++ Current Situation

I often now use the *ALL* keyword in process sensitiviy lists when generating verification models and, quite sensibly, this replaces any sensitivity list.

However, in the verification world I often use the *'TRANSACTION* attribute for control purposes and the use of the *ALL* keyword precludes the inclusion of this implicit signal.

---+++ Implementation details

It will require a rule change for sensitivity lists:

<sticky><pre><verbatim>
   process_sensitivity_list ::= all [ , implicit_sensitivity_list] | sensitivity_list

   implicit_sensitivity_list ::= implicit_signal_name { , implicit_signal_name }
</verbatim></pre></sticky>

---+++ Code Examples

<sticky><pre><verbatim>
   process my_model( all, sig'transaction) is
      ---
   begin
      ---
   end process my_model;
</verbatim></pre></sticky>

---++ Use Cases

---++ Arguments FOR

This requirement was probably just overlooked when adding the *ALL* keyword into the LRM.

---++ Arguments AGAINST

---++ General Comments

It may be beneficial to allow the *ALL* keyword (and implicit signals) to be used within the sensitivity clause of the *ON* keyword as part of the *WAIT* statement.

---++ Supporters

-- [[Main.BrentHahoe][Brent Hayhoe]] - 2014-05-30

_Add your signature here to indicate your support for the proposal_

Topic revision: r6 - 2020-02-17 - 15:34:25 - JimLewis

P1076