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nobs/hash/shake/xor_unaligned.go
Henry Case 49c7e4ae43 SHAKE: Don't use function pointers
* xorIn and copyOut function pointers cause input and output data
  to be moved to heap. This degrades performance of calling code.

* This change removes usage of those function pointers. We will always
  use unaligned implementation as it's faster (but may crash on some
  systems)

* Benchmark compares generic vs unaligned xorIn and copyOut

benchmark                          old ns/op     new ns/op     delta
BenchmarkPermutationFunction-4     463           815           +76.03%
BenchmarkShake128_MTU-4            4443          8180          +84.11%
BenchmarkShake256_MTU-4            4739          9060          +91.18%
BenchmarkShake256_16x-4            71886         132629        +84.50%
BenchmarkShake256_1MiB-4           3695138       6649012       +79.94%
BenchmarkCShake128_448_16x-4       21210         24611         +16.03%
BenchmarkCShake128_1MiB-4          3009342       3396496       +12.87%
BenchmarkCShake256_448_16x-4       26034         27785         +6.73%
BenchmarkCShake256_1MiB-4          3654713       3829404       +4.78%
2019-05-14 16:31:51 +01:00

54 lines
1012 B
Go

// Copyright 2015 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// +build amd64 386 ppc64le
// +build !appengine
package shake
import "unsafe"
func xorInUnaligned(d *state, buf []byte) {
bw := (*[maxRate / 8]uint64)(unsafe.Pointer(&buf[0]))
n := len(buf)
if n >= 72 {
d.a[0] ^= bw[0]
d.a[1] ^= bw[1]
d.a[2] ^= bw[2]
d.a[3] ^= bw[3]
d.a[4] ^= bw[4]
d.a[5] ^= bw[5]
d.a[6] ^= bw[6]
d.a[7] ^= bw[7]
d.a[8] ^= bw[8]
}
if n >= 104 {
d.a[9] ^= bw[9]
d.a[10] ^= bw[10]
d.a[11] ^= bw[11]
d.a[12] ^= bw[12]
}
if n >= 136 {
d.a[13] ^= bw[13]
d.a[14] ^= bw[14]
d.a[15] ^= bw[15]
d.a[16] ^= bw[16]
}
if n >= 144 {
d.a[17] ^= bw[17]
}
if n >= 168 {
d.a[18] ^= bw[18]
d.a[19] ^= bw[19]
d.a[20] ^= bw[20]
}
}
func copyOutUnaligned(d *state, buf []byte) {
ab := (*[maxRate]uint8)(unsafe.Pointer(&d.a[0]))
copy(buf, ab[:])
}
const xorImplementationUnaligned = "unaligned"