[vhdl-200x] RE: regarding resolution function for resolved signal with single source

From: Jones, Andy D <andy.d.jones@lmco.com>
Date: Thu Jul 24 2014 - 11:22:28 PDT
Some simulators, for standard resolution functions which are known not to modify the result when only one driver is present (transparent), will not call the resolution function if only one driver is present.

Otherwise, the resolution function is called for all signals of resolved type.

My proposal is to extend the resolution function call to variable assignments and associations (with a single-element array containing the value), for variables of a resolved subtype, in support of providing the desired modulo behavior for a resolved subtype of integer. In this case, the modulo resolution function would modify the assigned value.


Andy D Jones
Electrical Engineering
Lockheed Martin Missiles and Fire Control
Dallas TX


From: owner-vhdl-200x@eda.org [mailto:owner-vhdl-200x@eda.org] On Behalf Of Srivastava, Bineet
Sent: Wednesday, July 23, 2014 6:31 AM
To: vhdl-200x@eda.org
Cc: Srivastava, Bineet
Subject: EXTERNAL: [vhdl-200x] regarding resolution function for resolved signal with single source

Hi,

As per section (IEEE-Std 1076-2008)

4.6 Resolution functions
A resolution function is a function that defines how the values of multiple sources of a given signal are to be
resolved into a single value for that signal.



And as per section

14.7.3.2 Driving values
If S is a resolved signal and has one or more sources, then the driving values of the sources of S
are examined. It is an error if any of these driving values is a composite where one or more
subelement values are determined by the null transaction (see 10.5.2.2) and one or more
subelement values are not determined by the null transaction. If S is of signal kind register and
all the sources of S have values determined by the null transaction, then the driving value of S
is unchanged from its previous value. Otherwise, the driving value of S is obtained by
executing the resolution function associated with S, where that function is called with an input
parameter consisting of the concatenation of the driving values of the sources of S, with the
exception of the value of any source of S whose current value is determined by the null
transaction.


Please clarify, does the resolution function be applied on a resolved signal when it is driven by only one source?


Regards
Bineet

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Received on Thu Jul 24 11:24:37 2014

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