RE: [avr-gcc-list] Problem with delay loop

[Eric Weddington]

> -----Original Message-----
> From: John Regehr [mailto:address@hidden
> Sent: Monday, October 01, 2007 10:59 PM
> To: Eric Weddington
> Cc: 'Paulo Marques'; 'David Brown'; 'AVR-GCC'
> Subject: RE: [avr-gcc-list] Problem with delay loop
>
> > However, David brings up a good point. A local variable is
> put on the stack,
> > generally not the place for hardware to modify the
> variable. And generally,
> > other parts of the program (such as ISRs) don't have access
> to the specific
> > location of the variable on the stack. Both hardware and
> ISRs work with
> > global variables. So *could* a compiler reason that local
> variables could
> > never be volatile? Or are there truly situations where
> hardware or ISRs
> > could modify local variables on the stack?
>
> The common use of volatile automatic variables is in conjunction with
> setjmp/longjmp.  This idiom would break if volatile locals went into
> registers.

Ah, ok then. In practice, I have never needed to use setjmp/longjmp, so I
have a tendency to forget about these routines.

Thanks,
Eric