golang crc32_s390x 代码
文件路径：/src/hash/crc32/crc32_s390x.go
/ Copyright 2016 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
import "internal/cpu"
const (
vxMinLen = 64
vxAlignMask = 15 / align to 16 bytes
)
/ hasVX reports whether the machine has the z/Architecture
/ vector facility installed and enabled.
var hasVX = cpu.S390X.HasVX
/ vectorizedCastagnoli implements CRC32 using vector instructions.
/ It is defined in crc32_s390x.s.
/
/go:noescape
func vectorizedCastagnoli(crc uint32, p []byte) uint32
/ vectorizedIEEE implements CRC32 using vector instructions.
/ It is defined in crc32_s390x.s.
/
/go:noescape
func vectorizedIEEE(crc uint32, p []byte) uint32
func archAvailableCastagnoli() bool {
return hasVX
}
var archCastagnoliTable8 *slicing8Table
func archInitCastagnoli() {
if !hasVX {
panic("not available")
}
/ We still use slicing-by-8 for small buffers.
archCastagnoliTable8 = slicingMakeTable(Castagnoli)
}
/ archUpdateCastagnoli calculates the checksum of p using
/ vectorizedCastagnoli.
func archUpdateCastagnoli(crc uint32, p []byte) uint32 {
if !hasVX {
panic("not available")
}
/ Use vectorized function if data length is above threshold.
if len(p) >= vxMinLen {
aligned := len(p) & ^vxAlignMask
crc = vectorizedCastagnoli(crc, p[:aligned])
p = p[aligned:]
}
if len(p) == 0 {
return crc
}
return slicingUpdate(crc, archCastagnoliTable8, p)
}
func archAvailableIEEE() bool {
return hasVX
}
var archIeeeTable8 *slicing8Table
func archInitIEEE() {
if !hasVX {
panic("not available")
}
/ We still use slicing-by-8 for small buffers.
archIeeeTable8 = slicingMakeTable(IEEE)
}
/ archUpdateIEEE calculates the checksum of p using vectorizedIEEE.
func archUpdateIEEE(crc uint32, p []byte) uint32 {
if !hasVX {
panic("not available")
}
/ Use vectorized function if data length is above threshold.
if len(p) >= vxMinLen {
aligned := len(p) & ^vxAlignMask
crc = vectorizedIEEE(crc, p[:aligned])
p = p[aligned:]
}
if len(p) == 0 {
return crc
}
return slicingUpdate(crc, archIeeeTable8, p)
}