1 files changed, 56 insertions, 0 deletions
diff --git a/libgo/go/hash/crc32/crc32_amd64.go b/libgo/go/hash/crc32/crc32_amd64.go
new file mode 100644
index 00000000000..ab4e2b8c8cd
--- /dev/null
+++ b/libgo/go/hash/crc32/crc32_amd64.go
@@ -0,0 +1,56 @@
+// Copyright 2011 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 crc32
+
+// This file contains the code to call the SSE 4.2 version of the Castagnoli
+// and IEEE CRC.
+
+// haveSSE41/haveSSE42/haveCLMUL are defined in crc_amd64.s and use
+// CPUID to test for SSE 4.1, 4.2 and CLMUL support.
+func haveSSE41() bool
+func haveSSE42() bool
+func haveCLMUL() bool
+
+// castagnoliSSE42 is defined in crc_amd64.s and uses the SSE4.2 CRC32
+// instruction.
+//go:noescape
+func castagnoliSSE42(crc uint32, p []byte) uint32
+
+// ieeeCLMUL is defined in crc_amd64.s and uses the PCLMULQDQ
+// instruction as well as SSE 4.1.
+//go:noescape
+func ieeeCLMUL(crc uint32, p []byte) uint32
+
+var sse42 = haveSSE42()
+var useFastIEEE = haveCLMUL() && haveSSE41()
+
+func updateCastagnoli(crc uint32, p []byte) uint32 {
+	if sse42 {
+		return castagnoliSSE42(crc, p)
+	}
+	return update(crc, castagnoliTable, p)
+}
+
+func updateIEEE(crc uint32, p []byte) uint32 {
+	if useFastIEEE && len(p) >= 64 {
+		left := len(p) & 15
+		do := len(p) - left
+		crc = ^ieeeCLMUL(^crc, p[:do])
+		if left > 0 {
+			crc = update(crc, IEEETable, p[do:])
+		}
+		return crc
+	}
+
+	// only use slicing-by-8 when input is >= 4KB
+	if len(p) >= 4096 {
+		ieeeTable8Once.Do(func() {
+			ieeeTable8 = makeTable8(IEEE)
+		})
+		return updateSlicingBy8(crc, ieeeTable8, p)
+	}
+
+	return update(crc, IEEETable, p)
+}