1 files changed, 26 insertions, 0 deletions
diff --git a/src/internal/bytealg/index_amd64.go b/src/internal/bytealg/index_amd64.go
new file mode 100644
index 0000000..c7a1941
--- /dev/null
+++ b/src/internal/bytealg/index_amd64.go
@@ -0,0 +1,26 @@
+// 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 bytealg
+
+import "internal/cpu"
+
+const MaxBruteForce = 64
+
+func init() {
+	if cpu.X86.HasAVX2 {
+		MaxLen = 63
+	} else {
+		MaxLen = 31
+	}
+}
+
+// Cutover reports the number of failures of IndexByte we should tolerate
+// before switching over to Index.
+// n is the number of bytes processed so far.
+// See the bytes.Index implementation for details.
+func Cutover(n int) int {
+	// 1 error per 8 characters, plus a few slop to start.
+	return (n + 16) / 8
+}