Re: [avr-gcc-list] Question about gcc preprocessing and port/pin assignments

[E. Weddington]

Richard Urwin wrote:

> On Wednesday 08 Dec 2004 11:20 pm, Dave Hylands wrote:
>  
>
> > So, what this says to me, is that it's perfectly reasonable for the
> > compiler to take an expression like:
> >
> > x = 1 + 2 + 3;
> >
> > and compile it as:
> >
> > tmp = 1;
> > tmp += 2;
> > tmp += 3;
> > x = tmp;
> >
> > or as:
> >
> > x = 1;
> > x += 2;
> > x += 3;
> >    
>
> I would say that a volatile should only be written to as many times as 
> the code says. 
>  

Unfortunately, it's not what you say (or what one says) that counts. 
What matters is what the C standard specification says that counts.... 
Any language lawyers in the house care to comment? Can we get chapter 
and verse?