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// 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
// CRC.
// haveSSE42 is defined in crc_amd64p32.s and uses CPUID to test for SSE 4.2
// support.
func haveSSE42() bool
// castagnoliSSE42 is defined in crc_amd64.s and uses the SSE4.2 CRC32
// instruction.
//go:noescape
func castagnoliSSE42(crc uint32, p []byte) uint32
var sse42 = haveSSE42()
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 {
// 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)
}
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