[openbeos] Re: app_server: MMX/SSE help wanted

Christian Packmann wrote on Mon, 09 Aug 2004 23:03:49 +0200:
> Even for non-cacheable data and simple operations, SIMD processing (and use 
> of data prefetch instructions) can give more than decisive advantages.

Looks like somewhere between 2 and 3 times speedup for large data.

Sure are lots of shift instructions in the C code - that's what MMX does do all 
in one operation.  I wonder if it would be faster or slower with byte pointers 
and math rather than shift operations to extract the bytes.  I'd also check the 
generated code to make sure *src was not being reloaded for every operation 
(copy it to a local variable first in that case) and compile with optimization.

Anyway, it's nice to see those actual numbers!

- Alex

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