[Cbe-oss-dev] [RFC 3/3] powerpc: copy_4K_page tweaked for Cell

Arnd Bergmann arnd at arndb.de
Fri Jun 20 07:28:50 EST 2008


On Thursday 19 June 2008, Mark Nelson wrote:
>         .align  7
> _GLOBAL(copy_4K_page)
>         dcbt    0,r4            /* Prefetch ONE SRC cacheline */
> 
>         addi    r6,r3,-8        /* prepare for stdu */
>         addi    r4,r4,-8        /* prepare for ldu */
> 
>         li      r10,32          /* copy 32 cache lines for a 4K page */
>         li      r12,128+8               /* prefetch distance*/

Since you have a loop here anyway instead of the fully unrolled
code, why not provide a copy_64K_page function as well, jumping in
here?

The inline 64k copy_page function otherwise just adds code size,
as well as being a tiny bit slower. It may even be good to
have an out-of-line copy_64K_page for the regular code, just
calling copy_4K_page repeatedly.

	Arnd <><


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