Re: [Qemu-devel] [PATCH] Fix comparison which always returned false

[Anthony Liguori]

On 06/15/2010 07:27 PM, Richard Henderson wrote:
> On 06/15/2010 02:28 PM, Anthony Liguori wrote:
>    
> > On 06/15/2010 04:03 PM, Stefan Weil wrote:
> >      
> > > Comparing an 8 bit value with ~0 does not work as expected.
> > > Replace ~0 by UINT8_MAX in comparison and also in assignment
> > > (and fix coding style, too).
> > >
> > >        
> > Because when the uint8_t gets promoted, it doesn't get zero filled.  I'd
> > rather something a bit more obvious like HPET_INVALID_COUNT.
> >      
> Er, yes it does.  The problem is that it *did* get zero-extended,
> but ~0 is 0xffffffff, so the comparison fails.
>    

Typo on my part.  I meant one filled obviously.

Regards,

Anthony Liguori

> But I really agree with Jan Kiszka down-thread -- why do we need
> to signal this as a special case at all?
>
>
> r~
>