RE: [sv-bc] Mantis 2380: array assignment compatibility

> On the other hand, type equivalence of elements means that some kinds of
> unpacked array copy operation can be implemented as a simple memory
> block copy; the proposed relaxation would require implementations to do
> an element-by-element copy.

Only if the elements of the source and target arrays are of types that are
assignment compatible, but not equivalent.  If an assignment could be
implemented today using a simple memory block copy, it still could be
after the proposed change.

-- Brad


________________________________________
From: owner-sv-bc@eda.org [owner-sv-bc@eda.org] On Behalf Of jonathan.bromley@doulos.com [jonathan.bromley@doulos.com]
Sent: Wednesday, May 20, 2009 5:31 AM
To: sv-bc@eda.org
Subject: [sv-bc] Mantis 2380: array assignment compatibility

hi BC,

Towards the end of the ballot review, BC pushed across
to EC a few ballot items relating to the assignment
compatibility of unpacked arrays - Mantis 2380 covers
them all.  Although EC didn't have time to consider it
before the May 14 deadline, I would like to get a
proposal prepared ready for the recirculation.
Although this is now an EC matter, I'd be grateful for
any comments you may have on the following suggestions.

The critical question is whether it is OK (as I and
at least some other members of EC believe) to relax
the existing rules for unpacked array assignment
compatibility so that the elements of the source
and target arrays need only be of ASSIGNMENT COMPATIBLE
types, rather than the current stricter requirement
that source and target elements be of EQUIVALENT type.
This relaxation would automatically deal with a number
of areas where the LRM is currently self-contradictory
or, at least, confusing (the confusion has been
compounded by various changes introduced by Mantis
items 1447 and 1702, which were passed some time ago).

Another advantage of this proposed relaxation would be
that it removes a restriction that seems confusing and
unnecessary to many users.  On the other hand, type
equivalence of elements means that some kinds of
unpacked array copy operation can be implemented as
a simple memory block copy; the proposed relaxation
would require implementations to do an element-by-
element copy.

Thanks in advance for your thoughts on this.
--
Jonathan Bromley
Consultant

Doulos - Developing Design Know-how
VHDL * Verilog * SystemVerilog * SystemC * PSL * Perl * Tcl/Tk * Project
Services

Doulos Ltd. Church Hatch, 22 Market Place, Ringwood, Hampshire, BH24 1AW,
UK
Tel:  + 44 (0)1425 471223                       Email:
jonathan.bromley@doulos.com
Fax:  +44 (0)1425 471573                        http://www.doulos.com

--------------------------------------------------------------------------------
Doulos Ltd is registered in England and Wales with company no. 3723454
Its registered office is 4 Brackley Close, Bournemouth International
Airport,
        Christchurch, BH23 6SE, UK.

This message may contain personal views which are not the views of
Doulos, unless specifically stated.


--
This message has been scanned for viruses and
dangerous content by MailScanner, and is
believed to be clean.

-- 
This message has been scanned for viruses and
dangerous content by MailScanner, and is
believed to be clean.