Filippo Valsorda
85e5e33df3
Separated the complex buffering logic from key stream generation more clearly, added plenty of comments and generally refactored the Go implementation for readability. Made the interface with the generic/assembly cores smaller and more consistent, according to golang.org/wiki/TargetSpecific. We will recover the lost performance on unaligned calls by caching 3/4 of the first round across XORKeyStream invocations, which we now have complexity budget for. name old speed new speed delta ChaCha20/64-4 435MB/s ± 2% 429MB/s ± 2% -1.47% (p=0.013 n=10+9) ChaCha20/256-4 496MB/s ± 1% 493MB/s ± 2% ~ (p=0.280 n=10+10) ChaCha20/10x25-4 283MB/s ± 1% 274MB/s ± 2% -3.13% (p=0.000 n=10+10) ChaCha20/4096-4 494MB/s ± 1% 493MB/s ± 5% ~ (p=0.631 n=10+10) ChaCha20/100x40-4 421MB/s ± 3% 408MB/s ± 1% -3.14% (p=0.003 n=9+9) ChaCha20/65536-4 515MB/s ± 1% 519MB/s ± 3% ~ (p=0.161 n=7+10) ChaCha20/1000x65-4 501MB/s ± 2% 501MB/s ± 3% ~ (p=0.497 n=9+10) Also applied a fix for a lingering bug in the ppc64le assembly written by Lynn Boger <laboger@linux.vnet.ibm.com>. Updates golang/go#24485 Change-Id: I10cf24a7f10359b1b4ae63c9bb1946735b98ac9b Reviewed-on: https://go-review.googlesource.com/c/crypto/+/185439 Reviewed-by: Michael Munday <mike.munday@ibm.com>
42 lines
1.2 KiB
Go
42 lines
1.2 KiB
Go
// Copyright 2018 The Go Authors. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style
|
|
// license that can be found src the LICENSE file.
|
|
|
|
package chacha20
|
|
|
|
import "runtime"
|
|
|
|
// Platforms that have fast unaligned 32-bit little endian accesses.
|
|
const unaligned = runtime.GOARCH == "386" ||
|
|
runtime.GOARCH == "amd64" ||
|
|
runtime.GOARCH == "arm64" ||
|
|
runtime.GOARCH == "ppc64le" ||
|
|
runtime.GOARCH == "s390x"
|
|
|
|
// xor reads a little endian uint32 from src, XORs it with u and
|
|
// places the result in little endian byte order in dst.
|
|
func xor(dst, src []byte, u uint32) {
|
|
_, _ = src[3], dst[3] // eliminate bounds checks
|
|
if unaligned {
|
|
// The compiler should optimize this code into
|
|
// 32-bit unaligned little endian loads and stores.
|
|
// TODO: delete once the compiler does a reliably
|
|
// good job with the generic code below.
|
|
// See issue #25111 for more details.
|
|
v := uint32(src[0])
|
|
v |= uint32(src[1]) << 8
|
|
v |= uint32(src[2]) << 16
|
|
v |= uint32(src[3]) << 24
|
|
v ^= u
|
|
dst[0] = byte(v)
|
|
dst[1] = byte(v >> 8)
|
|
dst[2] = byte(v >> 16)
|
|
dst[3] = byte(v >> 24)
|
|
} else {
|
|
dst[0] = src[0] ^ byte(u)
|
|
dst[1] = src[1] ^ byte(u>>8)
|
|
dst[2] = src[2] ^ byte(u>>16)
|
|
dst[3] = src[3] ^ byte(u>>24)
|
|
}
|
|
}
|