Add AMD64 assembly implementation of Salsa20
* cipher/Makefile.am: Add 'salsa20-amd64.S'. * cipher/salsa20-amd64.S: New. * cipher/salsa20.c (USE_AMD64): New macro. [USE_AMD64] (_gcry_salsa20_amd64_keysetup, _gcry_salsa20_amd64_ivsetup) (_gcry_salsa20_amd64_encrypt_blocks): New prototypes. [USE_AMD64] (salsa20_keysetup, salsa20_ivsetup, salsa20_core): New. [!USE_AMD64] (salsa20_core): Change 'src' to non-constant, update block counter in 'salsa20_core' and return burn stack depth. [!USE_AMD64] (salsa20_keysetup, salsa20_ivsetup): New. (salsa20_do_setkey): Move generic key setup to 'salsa20_keysetup'. (salsa20_setkey): Fix burn stack depth. (salsa20_setiv): Move generic IV setup to 'salsa20_ivsetup'. (salsa20_do_encrypt_stream) [USE_AMD64]: Process large buffers in AMD64 implementation. (salsa20_do_encrypt_stream): Move stack burning to this function... (salsa20_encrypt_stream, salsa20r12_encrypt_stream): ...from these functions. * configure.ac [x86-64]: Add 'salsa20-amd64.lo'.
Patch adds fast AMD64 assembly implementation for Salsa20. This implementation
is based on public domain code by D. J. Bernstein and it is available at
http://cr.yp.to/snuffle.html (amd64-xmm6). Implementation gains extra speed
by processing four blocks in parallel with help SSE2 instructions.
Benchmark results on Intel Core i5-4570 (3.2 Ghz):
Before:
SALSA20 | nanosecs/byte mebibytes/sec cycles/byte
STREAM enc | 3.88 ns/B 246.0 MiB/s 12.41 c/B
STREAM dec | 3.88 ns/B 246.0 MiB/s 12.41 c/B
=SALSA20R12 | nanosecs/byte mebibytes/sec cycles/byte
STREAM enc | 2.46 ns/B 387.9 MiB/s 7.87 c/B STREAM dec | 2.46 ns/B 387.7 MiB/s 7.87 c/B
After:
SALSA20 | nanosecs/byte mebibytes/sec cycles/byte
STREAM enc | 0.985 ns/B 967.8 MiB/s 3.15 c/B
STREAM dec | 0.987 ns/B 966.5 MiB/s 3.16 c/B
=SALSA20R12 | nanosecs/byte mebibytes/sec cycles/byte
STREAM enc | 0.636 ns/B 1500.5 MiB/s 2.03 c/B STREAM dec | 0.636 ns/B 1499.2 MiB/s 2.04 c/B
- Signed-off-by: Jussi Kivilinna <jussi.kivilinna@iki.fi>