91 lines
2.1 KiB
Go
91 lines
2.1 KiB
Go
// Copyright 2016 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// +build s390x
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package crc32
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const (
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vxMinLen = 64
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vxAlignMask = 15 // align to 16 bytes
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)
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// hasVectorFacility reports whether the machine has the z/Architecture
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// vector facility installed and enabled.
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func hasVectorFacility() bool
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var hasVX = hasVectorFacility()
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// vectorizedCastagnoli implements CRC32 using vector instructions.
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// It is defined in crc32_s390x.s.
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//go:noescape
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func vectorizedCastagnoli(crc uint32, p []byte) uint32
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// vectorizedIEEE implements CRC32 using vector instructions.
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// It is defined in crc32_s390x.s.
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//go:noescape
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func vectorizedIEEE(crc uint32, p []byte) uint32
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func archAvailableCastagnoli() bool {
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return hasVX
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}
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var archCastagnoliTable8 *slicing8Table
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func archInitCastagnoli() {
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if !hasVX {
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panic("not available")
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}
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// We still use slicing-by-8 for small buffers.
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archCastagnoliTable8 = slicingMakeTable(Castagnoli)
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}
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// archUpdateCastagnoli calculates the checksum of p using
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// vectorizedCastagnoli.
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func archUpdateCastagnoli(crc uint32, p []byte) uint32 {
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if !hasVX {
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panic("not available")
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}
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// Use vectorized function if data length is above threshold.
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if len(p) >= vxMinLen {
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aligned := len(p) & ^vxAlignMask
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crc = vectorizedCastagnoli(crc, p[:aligned])
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p = p[aligned:]
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}
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if len(p) == 0 {
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return crc
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}
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return slicingUpdate(crc, archCastagnoliTable8, p)
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}
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func archAvailableIEEE() bool {
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return hasVX
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}
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var archIeeeTable8 *slicing8Table
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func archInitIEEE() {
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if !hasVX {
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panic("not available")
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}
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// We still use slicing-by-8 for small buffers.
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archIeeeTable8 = slicingMakeTable(IEEE)
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}
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// archUpdateIEEE calculates the checksum of p using vectorizedIEEE.
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func archUpdateIEEE(crc uint32, p []byte) uint32 {
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if !hasVX {
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panic("not available")
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}
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// Use vectorized function if data length is above threshold.
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if len(p) >= vxMinLen {
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aligned := len(p) & ^vxAlignMask
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crc = vectorizedIEEE(crc, p[:aligned])
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p = p[aligned:]
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}
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if len(p) == 0 {
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return crc
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}
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return slicingUpdate(crc, archIeeeTable8, p)
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}
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