Re: [Qemu-devel] [PATCH 1/5] BIT_RANGE convenience macro

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Paolo Bonzini (pbonzini@redhat.com) wrote:
> 
> 
> On 16/06/2016 19:12, Dr. David Alan Gilbert (git) wrote:
> > From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
> > 
> > e.g. BIT_RANGE(15, 0) gives 0xff00
> 
> That looks more like BIT_RANGE(15, 8). :)

Yes (and in the comment below) - I'll repost after
waiting to see if there's any other nasties.

Dave

> 
> Paolo
> 
> > Suggested by: Paolo Bonzini <pbonzini@redhat.com>
> > Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> > ---
> >  include/qemu/bitops.h | 3 +++
> >  1 file changed, 3 insertions(+)
> > 
> > diff --git a/include/qemu/bitops.h b/include/qemu/bitops.h
> > index 755fdd1..e411688 100644
> > --- a/include/qemu/bitops.h
> > +++ b/include/qemu/bitops.h
> > @@ -23,6 +23,9 @@
> >  #define BIT_MASK(nr)            (1UL << ((nr) % BITS_PER_LONG))
> >  #define BIT_WORD(nr)            ((nr) / BITS_PER_LONG)
> >  #define BITS_TO_LONGS(nr)       DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(long))
> > +/* e.g. BIT_RANGE(15, 0) -> 0xff00 */
> > +#define BIT_RANGE(hb, lb)     ((2ull << (hb)) - (1ull << (lb)))
> > +
> >  
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK