Re: [dpdk-dev] [PATCH v6 1/6] lib/eal: implement the family of rte bit operation APIs

[Honnappa Nagarahalli]

> 
> On Sat, 21 Dec 2019 16:07:23 +0000
> Honnappa Nagarahalli <honnappa.nagaraha...@arm.com> wrote:
> 
> > Converting these into macros will help remove the size based duplication of
> APIs. I came up with the following macro:
> >
> > #define RTE_GET_BIT(nr, var, ret, memorder) \ ({ \
> >     if (sizeof(var) == sizeof(uint32_t)) { \
> >         uint32_t mask1 = 1U << (nr)%32; \
> >         ret = __atomic_load_n(&var, (memorder)) & mask1;\
> >     } \
> >     else {\
> >         uint64_t mask2 = 1UL << (nr)%64;\
> >         ret = __atomic_load_n(&var, (memorder)) & mask2;\
> >     } \
> > })
> 
> 
> Follow on if you want to do it as macros, then use typeof() to make the mask
> any size.
Yes, that makes it much simple
#define RTE_GET_BIT(nr, var, ret, memorder) \ ({ \
     typeof(var) mask; \
     if (sizeof(var) == sizeof(uint32_t)) { \
         mask = 1U << (nr)%32; \
     } else {\
         mask = 1UL << (nr)%64;\
     } \
     ret = __atomic_load_n(&var, (memorder)) & mask;\
})