This patch optimizes Poly1305 for powerpc64 architecture by utilizing POWER9-specific instruction vmsumudm for full 64-bit multiplication applied on 4-blocks at parallel based on radix 2^44
The patch also adds new option --enable-power9 for configuration to compile Power ISA v3.0 code.
testsuite passes all tests of this patch.
Benchmark of poly1305 update using nettle-benchmark on Power9
| C | This patch |
|---|---|
| 472.63 Mbyte/s | 2140.15 Mbyte/s |