[Mesa-dev] [PATCH 1/5] gallium/util: add util_last_bit64

[Ilia Mirkin]

On Sun, May 24, 2015 at 5:47 AM, Marek Olšák <maraeo at gmail.com> wrote:
> From: Marek Olšák <marek.olsak at amd.com>
>
> This will be needed by radeonsi.

Then it should probably be included in a patch series that touches radeonsi...

Reviewed-by: Ilia Mirkin <imirkin at alum.mit.edu>

but I'd prefer it if you could push this along with radeonsi changes,
not just the core gallium ones.

> ---
>
> These 5 patches are picked from my tessellation branch.
>
>  src/gallium/auxiliary/util/u_math.h | 19 +++++++++++++++++++
>  1 file changed, 19 insertions(+)
>
> diff --git a/src/gallium/auxiliary/util/u_math.h b/src/gallium/auxiliary/util/u_math.h
> index 58070a9..3b4040f 100644
> --- a/src/gallium/auxiliary/util/u_math.h
> +++ b/src/gallium/auxiliary/util/u_math.h
> @@ -425,6 +425,25 @@ util_last_bit(unsigned u)
>  }
>
>  /**
> + * Find last bit set in a word.  The least significant bit is 1.
> + * Return 0 if no bits are set.
> + */
> +static INLINE unsigned
> +util_last_bit64(uint64_t u)
> +{
> +#if defined(HAVE___BUILTIN_CLZLL)
> +   return u == 0 ? 0 : 64 - __builtin_clzll(u);
> +#else
> +   unsigned r = 0;
> +   while (u) {
> +       r++;
> +       u >>= 1;
> +   }
> +   return r;
> +#endif
> +}
> +
> +/**
>   * Find last bit in a word that does not match the sign bit. The least
>   * significant bit is 1.
>   * Return 0 if no bits are set.
> --
> 2.1.0
>
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