| commit | 4efcac3a244de86593a82ca4ed945e839eb4c5af | [log] [tgz] |
|---|---|---|
| author | David S. Miller <davem@davemloft.net> | Wed May 23 19:20:20 2012 -0700 |
| committer | David S. Miller <davem@davemloft.net> | Wed May 23 19:20:20 2012 -0700 |
| tree | 7456cbb6d71b3f92385d94cab546e2b93dc19c6a | |
| parent | ff06dffbc8abfc60d6a0332f058f1d1bb01abb31 [diff] |
sparc: Optimize strncpy_from_user() zero byte search. Compute a mask that will only have 0x80 in the bytes which had a zero in them. The formula is: ~(((x & 0x7f7f7f7f) + 0x7f7f7f7f) | x | 0x7f7f7f7f) In the inner word iteration, we have to compute the "x | 0x7f7f7f7f" part, so we can reuse that in the above calculation. Once we have this mask, we perform divide and conquer to find the highest 0x80 location. Signed-off-by: David S. Miller <davem@davemloft.net>