[Mesa-dev] [PATCH 12/13] gallium/util: Add u_bit_scan_consecutive_range64.

[Nicolai Hähnle]

On 13.04.2016 20:35, Bas Nieuwenhuizen wrote:
> For use by radeonsi.
>
> Signed-off-by: Bas Nieuwenhuizen <bas at basnieuwenhuizen.nl>
> ---
>   src/gallium/auxiliary/util/u_math.h | 8 ++++++++
>   1 file changed, 8 insertions(+)
>
> diff --git a/src/gallium/auxiliary/util/u_math.h b/src/gallium/auxiliary/util/u_math.h
> index b4ac0db..3a468e4 100644
> --- a/src/gallium/auxiliary/util/u_math.h
> +++ b/src/gallium/auxiliary/util/u_math.h
> @@ -523,6 +523,14 @@ u_bit_scan_consecutive_range(unsigned *mask, int *start, int *count)
>      *mask &= ~(((1 << *count) - 1) << *start);
>   }
>
> +static inline void
> +u_bit_scan_consecutive_range64(uint64_t *mask, int *start, int *count)
> +{
> +   *start = ffsll(*mask) - 1;
> +   *count = ffsll(~(*mask >> *start)) - 1;
> +   *mask &= ~(((1llu << *count) - 1) << *start);
> +}
> +

I don't think this does the right thing when *mask is ~0llu: *start will 
be 0 (correct), *count will be -1, and *mask will most likely be undefined.

Thanks,
Nicolai

>   /**
>    * Return float bits.
>    */
>