1 files changed, 27 insertions, 0 deletions
diff --git a/src/crypto/cipher/xor_amd64.go b/src/crypto/cipher/xor_amd64.go
new file mode 100644
index 0000000..a595acc
--- /dev/null
+++ b/src/crypto/cipher/xor_amd64.go
@@ -0,0 +1,27 @@
+// Copyright 2018 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 cipher
+
+// xorBytes xors the bytes in a and b. The destination should have enough
+// space, otherwise xorBytes will panic. Returns the number of bytes xor'd.
+func xorBytes(dst, a, b []byte) int {
+	n := len(a)
+	if len(b) < n {
+		n = len(b)
+	}
+	if n == 0 {
+		return 0
+	}
+	_ = dst[n-1]
+	xorBytesSSE2(&dst[0], &a[0], &b[0], n) // amd64 must have SSE2
+	return n
+}
+
+func xorWords(dst, a, b []byte) {
+	xorBytes(dst, a, b)
+}
+
+//go:noescape
+func xorBytesSSE2(dst, a, b *byte, n int)