[avr-libc-dev] Re: gcc's avr implementation does not appear to be interrupt safe!

[E. Weddington]

Paul Schlie wrote:

> Well, good thing I didn't, as it is safe iff the interrupt routine
> prolog/epilogue is generated by GCC, as it does properly recognize that
> r1 may not be 0 at the point of interruption then pushes, clears, and
> then subsequently pops r1; so it's only assembly routines which were not
> declared to gcc as being so that would experience problems.
>
> (sorry for the false alarm, noticed the problem in interrupt routines which
> were not declared as such to gcc.)
>
>  
And that's why when somebody is writing assembler routines to interface 
with C routines they have to be aware of the ABI, which is described in 
a FAQ entry in the avr-libc user manual:
<http://www.nongnu.org/avr-libc/user-manual/FAQ.html#faq_reg_usage>

>  
>
> > From: Paul Schlie <address@hidden>
> > Date: Wed, 19 Jan 2005 13:16:52 -0500
> > To: "E. Weddington" <address@hidden>
> > Cc: Joerg Wunsch <address@hidden>
> > Subject: Re: gcc's avr implementation does not appear to be interrupt safe!
> >
> > Eric, the reason I posted it to only you two, was that it's likely a sensitive
> > observation; where I thought you might want to have a chance
> > to confirm or correct the observation prior to it being more broadly
> > stated that gcc for avr including winavr is inherently unsafe to use in
> > many circumstances.
> >
> >    
> >
> > > From: "E. Weddington" <address@hidden>
> > > And next time please post to a mailing list, preferrably avr-libc-dev
> > > (which I've CC'd) where the GCC maintainers (or at least one of them) is
> > > listening in.
> > >
> > > Eric
> > >      
>
>
>
>