algorithm suggested in following paper:

Câmara, D.; Gouvêa, C. P. L.; López, J. & Dahab, R.: Fast Software
Polynomial Multiplication on ARM Processors using the NEON Engine.

http://conradoplg.cryptoland.net/files/2010/12/mocrysen13.pdf

Modest improvement coefficients mean that code already had some
parallelism and there was not very much room for improvement. Special
thanks to Ted Krovetz for benchmarking the code with such patience.

ARM assembler modules.