[fpc-devel] using sse2 packed doubles

Vincent Snijders vsnijders at quicknet.nl
Thu Oct 12 14:07:43 CEST 2006


Florian Klaempfl wrote:
> Daniƫl Mantione schrieb:
>>
>> To get a large speedup, I think you should instead of making pairs of 
>> doubles, do the pixels in parallel. I.e. in this benchmark, a row is 
>> 3000 pixels wide, so, make an array of 3000 doubles, and do the 
>> operation with arrays. With proper compiler optimization, it should be 
>> possible to achieve speeds close to 2 flops a clock cycle.
> 
> 
> This is planned to be done, but currently it only spites an ie out :)

I added the spectralnorm benchmark to svn:
http://svn.freepascal.org/svn/fpc/trunk/tests/bench/shootout/src/spectralnorm.pp

It can serve as an example where large vectors can be used. The shootout 
uses n=2500.

Vincent



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