Joakim Tjernlund wrote:

quoted

I noticed that the lmw and stmw instructions are not used in copy_page(), clear_page() etc.
Aren't these instructions faster than a bunch of lwz/stw?

Motorola doesn't guarantee these are any faster, and most documentation indicates
they are likely to be slower.  If you look closely, you may notice that not
too many places can utilize these instructions, and often the load or store
is done to take advantages of some pipeline optimizations with comparisons
to values in well known registers.

Did some crude benchmarking using clear_page() as my test function.
I made a version that uses stmw and compared that with the orginal
clear_page().

Result:
 The stmw version was much slower. When I increased the number of
 bytes to copy per loop to 32, it became as fast as the orginal.

 Jocke


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