1 files changed, 34 insertions, 0 deletions
diff --git a/src/crypto/sha1/sha1block_amd64.go b/src/crypto/sha1/sha1block_amd64.go
new file mode 100644
index 0000000..039813d
--- /dev/null
+++ b/src/crypto/sha1/sha1block_amd64.go
@@ -0,0 +1,34 @@
+// Copyright 2016 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.
+
+package sha1
+
+import "internal/cpu"
+
+//go:noescape
+func blockAVX2(dig *digest, p []byte)
+
+//go:noescape
+func blockAMD64(dig *digest, p []byte)
+
+var useAVX2 = cpu.X86.HasAVX2 && cpu.X86.HasBMI1 && cpu.X86.HasBMI2
+
+func block(dig *digest, p []byte) {
+	if useAVX2 && len(p) >= 256 {
+		// blockAVX2 calculates sha1 for 2 block per iteration
+		// it also interleaves precalculation for next block.
+		// So it may read up-to 192 bytes past end of p
+		// We may add checks inside blockAVX2, but this will
+		// just turn it into a copy of blockAMD64,
+		// so call it directly, instead.
+		safeLen := len(p) - 128
+		if safeLen%128 != 0 {
+			safeLen -= 64
+		}
+		blockAVX2(dig, p[:safeLen])
+		blockAMD64(dig, p[safeLen:])
+	} else {
+		blockAMD64(dig, p)
+	}
+}