RE: [vhdl-200x-ft] Comment on FT22 re locally static array subtype

Ryan,

My comment referred only to the LRM before consideration of FT14. This is
clearly an area where coordination will be needed between the change
proposals.

Cheers,

PA

--
Dr. Peter J. Ashenden                        peter@ashenden.com.au
Ashenden Designs Pty. Ltd.                   www.ashenden.com.au
PO Box 640                                   Ph:  +61 8 8339 7532
Stirling, SA 5152                            Fax: +61 8 8339 2616
Australia                                    Mobile: +61 414 70 9106
> -----Original Message-----
> From: Hinton, Ryan W @ CSW-SLC [mailto:ryan.w.hinton@L-3com.com] 
> Sent: Wednesday, 15 December 2004 04:56
> To: 'Peter Ashenden'
> Cc: vhdl-200x-ft@eda.org
> Subject: RE: [vhdl-200x-ft] Comment on FT22 re locally static 
> array subtype
> 
> 
> 
> It is not clear whether this definition can be applied 
> recursively to arrays with unconstrained element types 
> (FT-14).  In other words, can I get a locally static array 
> subtype by applying a locally static index constraint to the 
> element type and array type?
> 
> type SIGNED_VECTOR is array (integer range <>) of SIGNED; 
> subtype SIGNED_4x3 is SIGNED_VECTOR(1 to 4).(2 downto 0);
> 
> Is SIGNED_4x3 a locally static subtype?
> 
> ---
> Ryan Hinton
> L-3 Communications / Communication Systems - West 
> ryan.w.hinton@L-3com.com
> 
> 
> -----Original Message-----
> From: Peter Ashenden [mailto:peter@ashenden.com.au]
> Sent: Monday, December 13, 2004 8:39 PM
> To: vhdl-200x-ft@eda.org
> Subject: [vhdl-200x-ft] Comment on FT22 re locally static 
> array subtype
> 
> 
> Folks,
> 
> In looking more closely at the wording in FT22, there appears 
> to be an issue.  The relevant part is:
> 
>   The line 606 in section 7.4.1 is changed from
> 
>   "A locally static array subtype is a constrained array 
> subtype formed 
>     by imposing on an unconstrained array type a locally static index 
>     constraint"
> 
>   to
> 
>   "A locally static array subtype is a constrained array 
> subtype formed 
>    by imposing on an unconstrained array type with a locally 
> static index 
>    constraint. The unconstained array type must have a 
> locally static element
>    subtype and locally static index subtype definitions."
> 
> First, there is no definition of a "locally static index 
> subtype definition".  However, that doesn't matter, since...
> 
> Second, a preceding sentence in that paragraph is
> 
>   A locally static index constraint is an index constraint 
> for which each
>   index subtype of the corresponding array type is locally 
> static and in
>   which each discrete range is locally static.
> 
> I think the intent of the proposed change was to specify 
> that, not only must the element subtype be locally static, 
> but the index subtypes, specified by the index subtype 
> definitions, also be locally static.  That requirement is 
> already captured in the definition of a locally static index 
> constraint, so there is no need to respecify it.  The changed 
> wording only need be
> 
>   "A locally static array subtype is a constrained array 
> subtype formed 
>    by imposing on an unconstrained array type with a locally 
> static index 
>    constraint. The unconstained array type must have a 
> locally static element
>    subtype."
> 
> Comments?
> 
> Cheers,
> 
> PA
> 
> --
> Dr. Peter J. Ashenden                        peter@ashenden.com.au
> Ashenden Designs Pty. Ltd.                   www.ashenden.com.au
> PO Box 640                                   Ph:  +61 8 8339 7532
> Stirling, SA 5152                            Fax: +61 8 8339 2616
> Australia                                    Mobile: +61 414 70 9106
>