Re: Zero_Fill pragma

[Jacob Sparre Andersen <sparre@nbi.dk>]

Nick Roberts wrote:

> The pragma is not intended to affect any of the bits that are used
> to represent a value. In a composite type, you sometimes get 'gaps'
> in between components (or possibly at the edges), of 'unused'
> bits. The pragma is intended to cause these unused bits to be
> initialised to 0 whenever the composite object as a whole is
> initialised. It is not intended to affect the initialisation (or
> reading or updating) of any of the components.
> 
> The purpose of the pragma is for use in interfacing, either with
> hardware or with data in any externally defined format.
> 
> It is quite often the case, when doing this, that a composite
> value has gaps which (according to the hardware design or data
> definition) must be kept 0.
> 
> Although this can be done explicitly using 'dummy' components, it is
> a pain doing so, and I think it can reduce the readability and
> maintainability of code. I think the suggested pragma would be
> better.

I disagree.

Although I can see that it is a bit of work to declare the parts of
the object that have to have a fixed value (it could also be 1 for
some hardware), but I still believe that it is better to do it
explicitly.

Jacob
-- 
"simply because no one had discovered a cure for the universe as a
 whole - or rather the only one that did exist had been abolished"