Re: [PATCH 4/7] bitops: Support 32 and 64 bit mask macro

[Yang Zhong]

On Wed, Sep 08, 2021 at 10:34:39AM +0200, Philippe Mathieu-Daudé wrote:
> On 9/8/21 10:19 AM, Yang Zhong wrote:
> > The Qemu should enable bit mask macro like Linux did in the
> > kernel, the GENMASK(h, l) and GENMASK_ULL(h, l) will set the
> > bit to 1 from l to h bit in the 32 bit or 64 bit long type.
> > 
> > Signed-off-by: Yang Zhong <yang.zhong@intel.com>
> > ---
> >  include/qemu/bitops.h | 7 +++++++
> >  1 file changed, 7 insertions(+)
> > 
> > diff --git a/include/qemu/bitops.h b/include/qemu/bitops.h
> > index 03213ce952..04dec60670 100644
> > --- a/include/qemu/bitops.h
> > +++ b/include/qemu/bitops.h
> > @@ -18,6 +18,7 @@
> >  
> >  #define BITS_PER_BYTE           CHAR_BIT
> >  #define BITS_PER_LONG           (sizeof (unsigned long) * BITS_PER_BYTE)
> > +#define BITS_PER_LONG_LONG       64
> >  
> >  #define BIT(nr)                 (1UL << (nr))
> >  #define BIT_ULL(nr)             (1ULL << (nr))
> > @@ -28,6 +29,12 @@
> >  #define MAKE_64BIT_MASK(shift, length) \
> >      (((~0ULL) >> (64 - (length))) << (shift))
> >  
> > +#define GENMASK(h, l) \
> > +    (((~0UL) << (l)) & (~0UL >> (BITS_PER_LONG - 1 - (h))))
> > +
> > +#define GENMASK_ULL(h, l) \
> > +    (((~0ULL) << (l)) & (~0ULL >> (BITS_PER_LONG_LONG - 1 - (h))))
> 
> What is the difference with MAKE_64BIT_MASK()??

  Philippe, thanks for comments, i will use MAKE_64BIT_MASK() to replace
  GENMASK_ULL(), and at the same time, this patch will be dropped, thanks!

  Yang