On 25.06.2024 21:07, Andrew Cooper wrote:
> --- a/xen/include/xen/bitops.h
> +++ b/xen/include/xen/bitops.h
> @@ -56,6 +56,16 @@ static always_inline __pure unsigned int ffs64(uint64_t x)
> return !x || (uint32_t)x ? ffs(x) : ffs(x >> 32) + 32;
> }
>
> +/*
> + * A type-generic ffs() which picks the appropriate ffs{,l,64}() based on
> it's
> + * argument.
> + */
> +#define ffs_g(x) \
> + sizeof(x) <= sizeof(int) ? ffs(x) : \
> + sizeof(x) <= sizeof(long) ? ffsl(x) : \
> + sizeof(x) <= sizeof(uint64_t) ? ffs64(x) : \
> + ({ BUILD_ERROR("ffs_g() Bad input type"); 0; })
I guess the lack of parentheses around the entire construct might be the
reason for the problems you're seeing, as that ...
> @@ -92,6 +102,20 @@ static always_inline __pure unsigned int fls64(uint64_t x)
> }
> }
>
> +/*
> + * for_each_set_bit() - Iterate over all set bits in a scalar value.
> + *
> + * @iter An iterator name. Scoped is within the loop only.
> + * @val A scalar value to iterate over.
> + *
> + * A copy of @val is taken internally.
> + */
> +#define for_each_set_bit(iter, val) \
> + for ( typeof(val) __v = (val); __v; ) \
> + for ( unsigned int (iter); \
> + __v && ((iter) = ffs_g(__v) - 1, true); \
... affects what effect the "- 1" here has.
Jan
