On 01/03/2013 12:53:13 PM, Alexander Graf wrote:
On 22.12.2012, at 03:15, Scott Wood wrote:
> Search the queue more efficiently by first looking for a non-zero
word,
> and then using the common bit-searching function to find the bit
within
> the word. It would be even nicer if bitops_ffsl() could be hooked
up
> to the compiler intrinsic so that bit-searching instructions could
be
> used, but that's another matter.
>
> Signed-off-by: Scott Wood <scottw...@freescale.com>
What we really want is a bitmap wide ffs() bipops helper function
that returns the first set bit in a bitmap and can optimize the hell
out of that operation inside of itself. I don't think this belongs to
the OpenPIC code.
Well, we do have find_next_bit() in bitops.c, but it looks
comparitively complicated in order to be generic and simply return a
value rather than perform an action on each bit set. I suspect that
the code in this patch would be faster, and avoids the need for me to
follow all the twists and turns of find_next_bit() to figure out
whether the undocumented interface is actually exactly what I guess it
to be (e.g. what does it return when no bit is found?).
-Scott
