ARM Skia NEON patches - 13 - S32A_Opaque





Blitrow32: S32A_Opaque code cleaning and speed improvement

- the old way of calculating alpha doesn't seem to be used anymore,
  so remove the remaining code
- adding prefetching allows to improve performance greatly in some
  cases at the expense of a little trade-off:

+-------+-----------+------------+
| count | Cortex-A9 | Cortex-A15 |
+-------+-----------+------------+
| 1,2   | 0         | 0          |
+-------+-----------+------------+
| 4     | 0         | -3%        |
+-------+-----------+------------+
| 8     | 0         | -4%        |
+-------+-----------+------------+
| 16    | 0         | -5%        |
+-------+-----------+------------+
| 64    | +14%      | 0          |
+-------+-----------+------------+
| 256   | +14%      | +12%       |
+-------+-----------+------------+
| 1024  | +115%     | +15%       |
+-------+-----------+------------+

BUG=
R=djsollen@google.com

Author: kevin.petit.arm@gmail.com

Review URL: https://chromiumcodereview.appspot.com/18459008

git-svn-id: http://skia.googlecode.com/svn/trunk@10026 2bbb7eff-a529-9590-31e7-b0007b416f81
1 file changed