This patch optimizes Poly1305 for arm64 architecture by using 2-way interleaving.
testsuite passes all tests of this patch.
Benchmark of poly1305 update using nettle-benchmark on gfarm 117
|650.67 Mbyte/s||923.22 Mbyte/s|
NOTE: This patch is implemented while both endianess modes are in mind but has been tested only on little-endian variant because of lack of big-endian access.