[opus] [Opus][RFC][FFT][Fixed-Point][NEON] NEON-Optimize Fixed-Point FFT?

Peter Robinson pbrobinson at gmail.com
Thu Dec 25 02:35:19 PST 2014

> I am working on DSP module of Ne10. I see there are fixed-point and
> floating-point FFT inside Opus. Is fixed-point FFT only a fall back for CPU
> without VFP? On ARMv7-A and ARMv8-A, benchmark result shows that fixed-point
> (int32) and floating-point (float32) FFT have similar performance. I guess
> fixed-point version is not often used on these platforms. Is it worth the
> effort to NEON-optimize fixed-point FFT?

Floating point units are optional on the ARM Cortex-M series so I
believe it might still be worth while. The Cortex-M3-7 are based on
the ARMv7 architecture.

[1] https://en.wikipedia.org/wiki/ARM_Cortex-M#Instruction_sets

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