Re: [PATCH v3 06/19] range: Introduce range_get_last_bit()

[Cédric Le Goater]

On 4/29/24 08:50, Zhenzhong Duan wrote:
> This helper get the highest 1 bit position of the upper bound.
>
> If the range is empty or upper bound is zero, -1 is returned.
>
> Suggested-by: Cédric Le Goater <clg@redhat.com>
> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
> ---
>   include/qemu/range.h | 11 +++++++++++
>   1 file changed, 11 insertions(+)
>
> diff --git a/include/qemu/range.h b/include/qemu/range.h
> index 205e1da76d..8e05bc1d9f 100644
> --- a/include/qemu/range.h
> +++ b/include/qemu/range.h
> @@ -20,6 +20,8 @@
>   #ifndef QEMU_RANGE_H
>   #define QEMU_RANGE_H
>   
> +#include "qemu/bitops.h"
> +
>   /*
>    * Operations on 64 bit address ranges.
>    * Notes:
> @@ -217,6 +219,15 @@ static inline int ranges_overlap(uint64_t first1, uint64_t 
> len1,
>       return !(last2 < first1 || last1 < first2);
>   }
>   
> +/* Get highest non-zero bit position of a range */
> +static inline int range_get_last_bit(Range *range)
> +{
> +    if (range_is_empty(range) || !range->upb) {
> +        return -1;
> +    }
> +    return find_last_bit(&range->upb, sizeof(range->upb));

This breaks builds on 32-bit host systems.


Thanks,

C.


> +}
> +
>   /*
>    * Return -1 if @a < @b, 1 @a > @b, and 0 if they touch or overlap.
>    * Both @a and @b must not be empty.