1 // Copyright 2016 The Go Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style
3 // license that can be found in the LICENSE file.
4 5 //go:build !purego
6 7 package sha1
8 9 import (
10 "crypto/internal/impl"
11 "internal/cpu"
12 )
13 14 //go:noescape
15 func blockAVX2(dig *digest, p []byte)
16 17 //go:noescape
18 func blockSHANI(dig *digest, p []byte)
19 20 var useAVX2 = cpu.X86.HasAVX && cpu.X86.HasAVX2 && cpu.X86.HasBMI1 && cpu.X86.HasBMI2
21 var useSHANI = cpu.X86.HasAVX && cpu.X86.HasSHA && cpu.X86.HasSSE41 && cpu.X86.HasSSSE3
22 23 func init() {
24 impl.Register("sha1", "AVX2", &useAVX2)
25 impl.Register("sha1", "SHA-NI", &useSHANI)
26 }
27 28 func block(dig *digest, p []byte) {
29 if useSHANI {
30 blockSHANI(dig, p)
31 } else if useAVX2 && len(p) >= 256 {
32 // blockAVX2 calculates sha1 for 2 block per iteration and also
33 // interleaves precalculation for next block. So it may read up-to 192
34 // bytes past end of p. We could add checks inside blockAVX2, but this
35 // would just turn it into a copy of the old pre-AVX2 amd64 SHA1
36 // assembly implementation, so just call blockGeneric instead.
37 safeLen := len(p) - 128
38 if safeLen%128 != 0 {
39 safeLen -= 64
40 }
41 blockAVX2(dig, p[:safeLen])
42 blockGeneric(dig, p[safeLen:])
43 } else {
44 blockGeneric(dig, p)
45 }
46 }
47