[SDL] SDL_memcpy variants used in SDL_BlitCopy

Ryan C. Gordon icculus at clutteredmind.org
Tue Sep 13 15:21:35 PDT 2005


> I am wondering is SDL_memcpyMMX() and SDL_memcpySSE() are actually faster
> than plain memcpy() on any Intel chips. My tests of copying 1Meg buffer of
> regular memory run on Windows 2000, 1.7MHz Intel Xeon show that the MMX
> version is 2-4% slower and the SSE version is ~45% *slower* than a regular
> intrinsic/inline memcpy() using "rep movsd".

Last time I checked, "rep movsd" was significantly slower (and was
horrified to find that this is what glibc does internally in its own
memcpy()).

Tried it on an AMD chip, though (it was either an Athlon MP or an early
Opteron, can't remember which).

--ryan.





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