Improve code with NEON on iOS - use VCEQ then VBIT

Question

I am writing a histogram like function which looks at vector data and then puts the elements in predefined "histogram" buckets based on which range they are closest to.

I can obviously do this using if condition but I am trying to improve it using NEON because these are image buffers.

One way to do this would be with VCEQ then VBIT but sadly enough I could not find VBIT in the header of neon. Alternatively I figured I could take the VCEQ results and do an exclusive AND with a vector of 1s and then use VBIF :-) but VBIF is not there either!

Any thoughts here? Thanks

Is it possible for you to share a pseudo algorithm on how you do this? — auselen, Feb 16 '13 at 04:01
@auselen, please see http://stackoverflow.com/questions/14926351/c-versus-vdsp-versus-neon-how-could-neon-be-as-slow-as-c — Khaled Barazi, Feb 17 '13 at 21:45

score 1 · Accepted Answer · answered Feb 15 '13 at 23:19

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VBIT, VBIF, and VBSL all do the same operation up to permutation of the sources; you can use the vbsl* intrinsics to get any of the three operations.

answered Feb 15 '13 at 23:19

Stephen Canon

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Stephen: if you can look at the follow up question, it would be much appreciated:http://stackoverflow.com/questions/14926351/c-versus-vdsp-versus-neon-how-could-neon-be-as-slow-as-c#comment20944212_14926351 – Khaled Barazi Feb 17 '13 at 22:02

Improve code with NEON on iOS - use VCEQ then VBIT

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