[FFmpeg-devel] Inline ASM vs. Intrinsics

castet.matthieu at free.fr castet.matthieu
Fri May 11 09:40:54 CEST 2007


Quoting Rich Felker <dalias at aerifal.cx>:
> Extending the C language with machine-specific intrinsics is a
> disgusting and misguided practice in principle as well.
IIRC there is also an extension to allow to work with vector in C in a portable
way (to do something like Intrinsics).

But in order to know the best vector's size, you need to know your machine
register size...

> C is for
> writing the code that's portable between machines, ASM is for writing
> machine-specific optimizations. There's no excuse for polluting C with
> machine-specific stuff.
But even if C, if you want to write optimized stuff, you need to know the
machine (floating point vs fix point, ...).


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