On Fri, Oct 26, 2012 at 11:36:06AM +0900, Simon Horman wrote:
> Make use of __builtin_clz if available which should optimize
> ofputil_version_bitmap_scanr() by replacing a loop with
> a single CLZ instruction when available.
>
> I'm unsure if this approach is worth it or not.
> But a similar approach could be taken to use ffs()
> in bitmap_scan().
>
> Signed-off-by: Simon Horman <ho...@verge.net.au>
I didn't notice this until now; I see now that I implemented something
with the same purpose as:
/* Returns the index of the rightmost 1-bit in 'x' (e.g. 01011000 => 6), or 32
* if 'x' is 0.
*
* This function only works with 32-bit integers. */
static inline uint32_t
leftmost_1bit_idx(uint32_t x)
{
return x ? log_2_floor(x) : 32;
}
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