[Libre-soc-dev] [RFC] REMAP, SHAPE, complex (full) FFT

[Luke Kenneth Casson Leighton]

https://github.com/Bulat-Ziganshin/FastECC/blob/master/ntt.cpp#L252

FFT in Galois Field.  i see no reason why the generic abstract REMAP
schedule should not be applied to Reed Solomon.

the Butterfly Schedule is that generic.

we are adding general purpose GF as part of bitmanip, so again it
should literally be around 25 lines of assembler, for any sized
RADIX2.

look further down in that source code there is even a bitreverse load
which can be replaced with 2 lines of assembler.

once done it will not need to be done ever again.

i am kinda surprised at the number of high profile applications a
butterfly REMAP schedule has.

Reed-Solomon is in QR Codes, RAID drives, space commonications, it
even went into Voyager.

l.