github.com/varialus/godfly@v0.0.0-20130904042352-1934f9f095ab/src/pkg/hash/crc32/crc32_amd64.go (about)

     1  // Copyright 2011 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package crc32
     6  
     7  // This file contains the code to call the SSE 4.2 version of the Castagnoli
     8  // CRC.
     9  
    10  // haveSSE42 is defined in crc_amd64.s and uses CPUID to test for SSE 4.2
    11  // support.
    12  func haveSSE42() bool
    13  
    14  // castagnoliSSE42 is defined in crc_amd64.s and uses the SSE4.2 CRC32
    15  // instruction.
    16  func castagnoliSSE42(crc uint32, p []byte) uint32
    17  
    18  var sse42 = haveSSE42()
    19  
    20  func updateCastagnoli(crc uint32, p []byte) uint32 {
    21  	if sse42 {
    22  		return castagnoliSSE42(crc, p)
    23  	}
    24  	return update(crc, castagnoliTable, p)
    25  }