Re: Pragma Volatile

[Jeffrey Carter <jrcarter@acm.org>]

Robert Dewar wrote:
> 
> Jeffrey Carter <jrcarter@acm.org> wrote in message news:<3BB64B13.81AFFB4D@acm.org>...
> > If a register is an Integer, I would generally do
> >
> > B : Integer;
> > for B'Address use Register_Location;
> > pragma Volatile (B);
> > ...
> > B := 0;
> > B := 1;
> >
> > But then, I don't have the C pointer fixation.
> 
> Be very careful about assumptions here. Suppose that
> B is a 32-bit word, then there is nothing in the language
> that says that
> 
>   B := 0;
> 
> has to generate a 32-bit store, it would be perfectly
> valid if the compiler generated a call to bcopy that
> moved four bytes independently (inefficient, but not
> incorrect).

Thanks again to Robert Dewar for pointing out implicit assumptions.

I was actually responding to Corey Minyard's implicit assumption that a
pointer was needed to access a memory-mapped hardware register.

-- 
Jeff Carter
"Monsieur Arthur King, who has the brain of a duck, you know."
Monty Python & the Holy Grail