Re: [sv-bc] FW: BOUNCE sv-bc@eda.org: Non-member submission from ["Rohit K. Jain" <rohit_jain@mentorg.com>]

From: Steven Sharp <sharp_at_.....>
Date: Wed Mar 02 2005 - 17:04:48 PST
>I would have prefered to see the signing keyword bind tightly to
>the nearest "{" or "[" to its right.  Somehow that option was discarded
>during the committee work, and perhaps this is for the best.  It
>encourages naming the datatypes which have interesting properties.

The Cadence datatypes proposal to IEEE 1364 did it this way.  I consider
it an advantage of conceptual cleanness that an arbitrary datatype could
be declared without having to use a typedef for the intermediate types.

Most people did tend to get confused when first confronted with something
like

logic signed [7:0] signed [1:0] [1:0] word;

They didn't understand the meaning of the signedness on the different
ranges.  But then they might be playing with packed arrays and ask
whether there wasn't some way to make one of the partially indexed
values signed.  Then they would finally understand the capability that
was provided by attaching a signedness to each range.  Perhaps the
concept of packed dimensions is too confusing to start with, and it
takes a while to understand that well enough to see the meaning of
specifying signedness for different levels.

Steven Sharp
sharp@cadence.com
Received on Wed Mar 2 17:04:52 2005

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