Commit 71108195 by Torkel Ödegaard

lib: updated dependency, fixes #7579

parent dce63ec1
# Compiled Object files, Static and Dynamic libs (Shared Objects)
*.o
*.a
*.so
# Folders
_obj
_test
# Architecture specific extensions/prefixes
*.[568vq]
[568vq].out
*.cgo1.go
*.cgo2.c
_cgo_defun.c
_cgo_gotypes.go
_cgo_export.*
_testmain.go
*.exe
*.test
*.prof
language: go
go:
- 1.3
- 1.4
- 1.5
- tip
script:
- go test -v .
- go test -v -race .
......@@ -12,12 +12,15 @@ Install using `go get github.com/klauspost/crc32`. This library is based on Go 1
Replace `import "hash/crc32"` with `import "github.com/klauspost/crc32"` and you are good to go.
# changes
* Oct 20, 2016: Changes have been merged to upstream Go. Package updated to match.
* Dec 4, 2015: Uses the "slice-by-8" trick more extensively, which gives a 1.5 to 2.5x speedup if assembler is unavailable.
# performance
For *Go 1.7* performance is equivalent to the standard library. So if you use this package for Go 1.7 you can switch back.
For IEEE tables (the most common), there is approximately a factor 10 speedup with "CLMUL" (Carryless multiplication) instruction:
```
benchmark old ns/op new ns/op delta
......
......@@ -40,70 +40,96 @@ const (
// Table is a 256-word table representing the polynomial for efficient processing.
type Table [256]uint32
// This file makes use of functions implemented in architecture-specific files.
// The interface that they implement is as follows:
//
// // archAvailableIEEE reports whether an architecture-specific CRC32-IEEE
// // algorithm is available.
// archAvailableIEEE() bool
//
// // archInitIEEE initializes the architecture-specific CRC3-IEEE algorithm.
// // It can only be called if archAvailableIEEE() returns true.
// archInitIEEE()
//
// // archUpdateIEEE updates the given CRC32-IEEE. It can only be called if
// // archInitIEEE() was previously called.
// archUpdateIEEE(crc uint32, p []byte) uint32
//
// // archAvailableCastagnoli reports whether an architecture-specific
// // CRC32-C algorithm is available.
// archAvailableCastagnoli() bool
//
// // archInitCastagnoli initializes the architecture-specific CRC32-C
// // algorithm. It can only be called if archAvailableCastagnoli() returns
// // true.
// archInitCastagnoli()
//
// // archUpdateCastagnoli updates the given CRC32-C. It can only be called
// // if archInitCastagnoli() was previously called.
// archUpdateCastagnoli(crc uint32, p []byte) uint32
// castagnoliTable points to a lazily initialized Table for the Castagnoli
// polynomial. MakeTable will always return this value when asked to make a
// Castagnoli table so we can compare against it to find when the caller is
// using this polynomial.
var castagnoliTable *Table
var castagnoliTable8 *slicing8Table
var castagnoliArchImpl bool
var updateCastagnoli func(crc uint32, p []byte) uint32
var castagnoliOnce sync.Once
func castagnoliInit() {
castagnoliTable = makeTable(Castagnoli)
castagnoliTable8 = makeTable8(Castagnoli)
castagnoliTable = simpleMakeTable(Castagnoli)
castagnoliArchImpl = archAvailableCastagnoli()
if castagnoliArchImpl {
archInitCastagnoli()
updateCastagnoli = archUpdateCastagnoli
} else {
// Initialize the slicing-by-8 table.
castagnoliTable8 = slicingMakeTable(Castagnoli)
updateCastagnoli = func(crc uint32, p []byte) uint32 {
return slicingUpdate(crc, castagnoliTable8, p)
}
}
}
// IEEETable is the table for the IEEE polynomial.
var IEEETable = makeTable(IEEE)
// slicing8Table is array of 8 Tables
type slicing8Table [8]Table
// iEEETable8 is the slicing8Table for IEEE
var iEEETable8 *slicing8Table
var iEEETable8Once sync.Once
var IEEETable = simpleMakeTable(IEEE)
// ieeeTable8 is the slicing8Table for IEEE
var ieeeTable8 *slicing8Table
var ieeeArchImpl bool
var updateIEEE func(crc uint32, p []byte) uint32
var ieeeOnce sync.Once
func ieeeInit() {
ieeeArchImpl = archAvailableIEEE()
if ieeeArchImpl {
archInitIEEE()
updateIEEE = archUpdateIEEE
} else {
// Initialize the slicing-by-8 table.
ieeeTable8 = slicingMakeTable(IEEE)
updateIEEE = func(crc uint32, p []byte) uint32 {
return slicingUpdate(crc, ieeeTable8, p)
}
}
}
// MakeTable returns the Table constructed from the specified polynomial.
// MakeTable returns a Table constructed from the specified polynomial.
// The contents of this Table must not be modified.
func MakeTable(poly uint32) *Table {
switch poly {
case IEEE:
ieeeOnce.Do(ieeeInit)
return IEEETable
case Castagnoli:
castagnoliOnce.Do(castagnoliInit)
return castagnoliTable
}
return makeTable(poly)
}
// makeTable returns the Table constructed from the specified polynomial.
func makeTable(poly uint32) *Table {
t := new(Table)
for i := 0; i < 256; i++ {
crc := uint32(i)
for j := 0; j < 8; j++ {
if crc&1 == 1 {
crc = (crc >> 1) ^ poly
} else {
crc >>= 1
}
}
t[i] = crc
}
return t
}
// makeTable8 returns slicing8Table constructed from the specified polynomial.
func makeTable8(poly uint32) *slicing8Table {
t := new(slicing8Table)
t[0] = *makeTable(poly)
for i := 0; i < 256; i++ {
crc := t[0][i]
for j := 1; j < 8; j++ {
crc = t[0][crc&0xFF] ^ (crc >> 8)
t[j][i] = crc
}
}
return t
return simpleMakeTable(poly)
}
// digest represents the partial evaluation of a checksum.
......@@ -114,10 +140,17 @@ type digest struct {
// New creates a new hash.Hash32 computing the CRC-32 checksum
// using the polynomial represented by the Table.
func New(tab *Table) hash.Hash32 { return &digest{0, tab} }
// Its Sum method will lay the value out in big-endian byte order.
func New(tab *Table) hash.Hash32 {
if tab == IEEETable {
ieeeOnce.Do(ieeeInit)
}
return &digest{0, tab}
}
// NewIEEE creates a new hash.Hash32 computing the CRC-32 checksum
// using the IEEE polynomial.
// Its Sum method will lay the value out in big-endian byte order.
func NewIEEE() hash.Hash32 { return New(IEEETable) }
func (d *digest) Size() int { return Size }
......@@ -126,43 +159,32 @@ func (d *digest) BlockSize() int { return 1 }
func (d *digest) Reset() { d.crc = 0 }
func update(crc uint32, tab *Table, p []byte) uint32 {
crc = ^crc
for _, v := range p {
crc = tab[byte(crc)^v] ^ (crc >> 8)
}
return ^crc
}
// updateSlicingBy8 updates CRC using Slicing-by-8
func updateSlicingBy8(crc uint32, tab *slicing8Table, p []byte) uint32 {
crc = ^crc
for len(p) > 8 {
crc ^= uint32(p[0]) | uint32(p[1])<<8 | uint32(p[2])<<16 | uint32(p[3])<<24
crc = tab[0][p[7]] ^ tab[1][p[6]] ^ tab[2][p[5]] ^ tab[3][p[4]] ^
tab[4][crc>>24] ^ tab[5][(crc>>16)&0xFF] ^
tab[6][(crc>>8)&0xFF] ^ tab[7][crc&0xFF]
p = p[8:]
}
crc = ^crc
if len(p) == 0 {
return crc
}
return update(crc, &tab[0], p)
}
// Update returns the result of adding the bytes in p to the crc.
func Update(crc uint32, tab *Table, p []byte) uint32 {
if tab == castagnoliTable {
switch tab {
case castagnoliTable:
return updateCastagnoli(crc, p)
} else if tab == IEEETable {
case IEEETable:
// Unfortunately, because IEEETable is exported, IEEE may be used without a
// call to MakeTable. We have to make sure it gets initialized in that case.
ieeeOnce.Do(ieeeInit)
return updateIEEE(crc, p)
default:
return simpleUpdate(crc, tab, p)
}
return update(crc, tab, p)
}
func (d *digest) Write(p []byte) (n int, err error) {
d.crc = Update(d.crc, d.tab, p)
switch d.tab {
case castagnoliTable:
d.crc = updateCastagnoli(d.crc, p)
case IEEETable:
// We only create digest objects through New() which takes care of
// initialization in this case.
d.crc = updateIEEE(d.crc, p)
default:
d.crc = simpleUpdate(d.crc, d.tab, p)
}
return len(p), nil
}
......@@ -179,4 +201,7 @@ func Checksum(data []byte, tab *Table) uint32 { return Update(0, tab, data) }
// ChecksumIEEE returns the CRC-32 checksum of data
// using the IEEE polynomial.
func ChecksumIEEE(data []byte) uint32 { return updateIEEE(0, data) }
func ChecksumIEEE(data []byte) uint32 {
ieeeOnce.Do(ieeeInit)
return updateIEEE(0, data)
}
//+build !appengine,!gccgo
// 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.
// +build !appengine,!gccgo
// AMD64-specific hardware-assisted CRC32 algorithms. See crc32.go for a
// description of the interface that each architecture-specific file
// implements.
package crc32
import "unsafe"
// 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 uses
// 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
// castagnoliSSE42 is defined in crc32_amd64.s and uses the SSE4.2 CRC32
// instruction.
// go:noescape
//go:noescape
func castagnoliSSE42(crc uint32, p []byte) uint32
// castagnoliSSE42Triple is defined in crc32_amd64.s and uses the SSE4.2 CRC32
// instruction.
//go:noescape
func castagnoliSSE42Triple(
crcA, crcB, crcC uint32,
a, b, c []byte,
rounds uint32,
) (retA uint32, retB uint32, retC uint32)
// ieeeCLMUL is defined in crc_amd64.s and uses the PCLMULQDQ
// instruction as well as SSE 4.1.
// go:noescape
//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)
const castagnoliK1 = 168
const castagnoliK2 = 1344
type sse42Table [4]Table
var castagnoliSSE42TableK1 *sse42Table
var castagnoliSSE42TableK2 *sse42Table
func archAvailableCastagnoli() bool {
return sse42
}
func archInitCastagnoli() {
if !sse42 {
panic("arch-specific Castagnoli not available")
}
// only use slicing-by-8 when input is >= 16 Bytes
if len(p) >= 16 {
return updateSlicingBy8(crc, castagnoliTable8, p)
castagnoliSSE42TableK1 = new(sse42Table)
castagnoliSSE42TableK2 = new(sse42Table)
// See description in updateCastagnoli.
// t[0][i] = CRC(i000, O)
// t[1][i] = CRC(0i00, O)
// t[2][i] = CRC(00i0, O)
// t[3][i] = CRC(000i, O)
// where O is a sequence of K zeros.
var tmp [castagnoliK2]byte
for b := 0; b < 4; b++ {
for i := 0; i < 256; i++ {
val := uint32(i) << uint32(b*8)
castagnoliSSE42TableK1[b][i] = castagnoliSSE42(val, tmp[:castagnoliK1])
castagnoliSSE42TableK2[b][i] = castagnoliSSE42(val, tmp[:])
}
}
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:])
// castagnoliShift computes the CRC32-C of K1 or K2 zeroes (depending on the
// table given) with the given initial crc value. This corresponds to
// CRC(crc, O) in the description in updateCastagnoli.
func castagnoliShift(table *sse42Table, crc uint32) uint32 {
return table[3][crc>>24] ^
table[2][(crc>>16)&0xFF] ^
table[1][(crc>>8)&0xFF] ^
table[0][crc&0xFF]
}
func archUpdateCastagnoli(crc uint32, p []byte) uint32 {
if !sse42 {
panic("not available")
}
// This method is inspired from the algorithm in Intel's white paper:
// "Fast CRC Computation for iSCSI Polynomial Using CRC32 Instruction"
// The same strategy of splitting the buffer in three is used but the
// combining calculation is different; the complete derivation is explained
// below.
//
// -- The basic idea --
//
// The CRC32 instruction (available in SSE4.2) can process 8 bytes at a
// time. In recent Intel architectures the instruction takes 3 cycles;
// however the processor can pipeline up to three instructions if they
// don't depend on each other.
//
// Roughly this means that we can process three buffers in about the same
// time we can process one buffer.
//
// The idea is then to split the buffer in three, CRC the three pieces
// separately and then combine the results.
//
// Combining the results requires precomputed tables, so we must choose a
// fixed buffer length to optimize. The longer the length, the faster; but
// only buffers longer than this length will use the optimization. We choose
// two cutoffs and compute tables for both:
// - one around 512: 168*3=504
// - one around 4KB: 1344*3=4032
//
// -- The nitty gritty --
//
// Let CRC(I, X) be the non-inverted CRC32-C of the sequence X (with
// initial non-inverted CRC I). This function has the following properties:
// (a) CRC(I, AB) = CRC(CRC(I, A), B)
// (b) CRC(I, A xor B) = CRC(I, A) xor CRC(0, B)
//
// Say we want to compute CRC(I, ABC) where A, B, C are three sequences of
// K bytes each, where K is a fixed constant. Let O be the sequence of K zero
// bytes.
//
// CRC(I, ABC) = CRC(I, ABO xor C)
// = CRC(I, ABO) xor CRC(0, C)
// = CRC(CRC(I, AB), O) xor CRC(0, C)
// = CRC(CRC(I, AO xor B), O) xor CRC(0, C)
// = CRC(CRC(I, AO) xor CRC(0, B), O) xor CRC(0, C)
// = CRC(CRC(CRC(I, A), O) xor CRC(0, B), O) xor CRC(0, C)
//
// The castagnoliSSE42Triple function can compute CRC(I, A), CRC(0, B),
// and CRC(0, C) efficiently. We just need to find a way to quickly compute
// CRC(uvwx, O) given a 4-byte initial value uvwx. We can precompute these
// values; since we can't have a 32-bit table, we break it up into four
// 8-bit tables:
//
// CRC(uvwx, O) = CRC(u000, O) xor
// CRC(0v00, O) xor
// CRC(00w0, O) xor
// CRC(000x, O)
//
// We can compute tables corresponding to the four terms for all 8-bit
// values.
crc = ^crc
// If a buffer is long enough to use the optimization, process the first few
// bytes to align the buffer to an 8 byte boundary (if necessary).
if len(p) >= castagnoliK1*3 {
delta := int(uintptr(unsafe.Pointer(&p[0])) & 7)
if delta != 0 {
delta = 8 - delta
crc = castagnoliSSE42(crc, p[:delta])
p = p[delta:]
}
return crc
}
// only use slicing-by-8 when input is >= 16 Bytes
if len(p) >= 16 {
iEEETable8Once.Do(func() {
iEEETable8 = makeTable8(IEEE)
})
return updateSlicingBy8(crc, iEEETable8, p)
// Process 3*K2 at a time.
for len(p) >= castagnoliK2*3 {
// Compute CRC(I, A), CRC(0, B), and CRC(0, C).
crcA, crcB, crcC := castagnoliSSE42Triple(
crc, 0, 0,
p, p[castagnoliK2:], p[castagnoliK2*2:],
castagnoliK2/24)
// CRC(I, AB) = CRC(CRC(I, A), O) xor CRC(0, B)
crcAB := castagnoliShift(castagnoliSSE42TableK2, crcA) ^ crcB
// CRC(I, ABC) = CRC(CRC(I, AB), O) xor CRC(0, C)
crc = castagnoliShift(castagnoliSSE42TableK2, crcAB) ^ crcC
p = p[castagnoliK2*3:]
}
// Process 3*K1 at a time.
for len(p) >= castagnoliK1*3 {
// Compute CRC(I, A), CRC(0, B), and CRC(0, C).
crcA, crcB, crcC := castagnoliSSE42Triple(
crc, 0, 0,
p, p[castagnoliK1:], p[castagnoliK1*2:],
castagnoliK1/24)
// CRC(I, AB) = CRC(CRC(I, A), O) xor CRC(0, B)
crcAB := castagnoliShift(castagnoliSSE42TableK1, crcA) ^ crcB
// CRC(I, ABC) = CRC(CRC(I, AB), O) xor CRC(0, C)
crc = castagnoliShift(castagnoliSSE42TableK1, crcAB) ^ crcC
p = p[castagnoliK1*3:]
}
// Use the simple implementation for what's left.
crc = castagnoliSSE42(crc, p)
return ^crc
}
func archAvailableIEEE() bool {
return useFastIEEE
}
var archIeeeTable8 *slicing8Table
func archInitIEEE() {
if !useFastIEEE {
panic("not available")
}
// We still use slicing-by-8 for small buffers.
archIeeeTable8 = slicingMakeTable(IEEE)
}
func archUpdateIEEE(crc uint32, p []byte) uint32 {
if !useFastIEEE {
panic("not available")
}
return update(crc, IEEETable, p)
if len(p) >= 64 {
left := len(p) & 15
do := len(p) - left
crc = ^ieeeCLMUL(^crc, p[:do])
p = p[do:]
}
if len(p) == 0 {
return crc
}
return slicingUpdate(crc, archIeeeTable8, p)
}
//+build gc
// 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.
// +build gc
#define NOSPLIT 4
#define RODATA 8
// castagnoliSSE42 updates the (non-inverted) crc with the given buffer.
//
// func castagnoliSSE42(crc uint32, p []byte) uint32
TEXT ·castagnoliSSE42(SB), NOSPLIT, $0
MOVL crc+0(FP), AX // CRC value
MOVQ p+8(FP), SI // data pointer
MOVQ p_len+16(FP), CX // len(p)
NOTL AX
// If there's less than 8 bytes to process, we do it byte-by-byte.
// If there are fewer than 8 bytes to process, skip alignment.
CMPQ CX, $8
JL cleanup
JL less_than_8
// Process individual bytes until the input is 8-byte aligned.
startup:
MOVQ SI, BX
ANDQ $7, BX
JZ aligned
// Process the first few bytes to 8-byte align the input.
// BX = 8 - BX. We need to process this many bytes to align.
SUBQ $1, BX
XORQ $7, BX
BTQ $0, BX
JNC align_2
CRC32B (SI), AX
DECQ CX
INCQ SI
JMP startup
align_2:
BTQ $1, BX
JNC align_4
// CRC32W (SI), AX
BYTE $0x66; BYTE $0xf2; BYTE $0x0f; BYTE $0x38; BYTE $0xf1; BYTE $0x06
SUBQ $2, CX
ADDQ $2, SI
align_4:
BTQ $2, BX
JNC aligned
// CRC32L (SI), AX
BYTE $0xf2; BYTE $0x0f; BYTE $0x38; BYTE $0xf1; BYTE $0x06
SUBQ $4, CX
ADDQ $4, SI
aligned:
// The input is now 8-byte aligned and we can process 8-byte chunks.
CMPQ CX, $8
JL cleanup
JL less_than_8
CRC32Q (SI), AX
ADDQ $8, SI
SUBQ $8, CX
JMP aligned
cleanup:
// We may have some bytes left over that we process one at a time.
CMPQ CX, $0
JE done
less_than_8:
// We may have some bytes left over; process 4 bytes, then 2, then 1.
BTQ $2, CX
JNC less_than_4
// CRC32L (SI), AX
BYTE $0xf2; BYTE $0x0f; BYTE $0x38; BYTE $0xf1; BYTE $0x06
ADDQ $4, SI
less_than_4:
BTQ $1, CX
JNC less_than_2
// CRC32W (SI), AX
BYTE $0x66; BYTE $0xf2; BYTE $0x0f; BYTE $0x38; BYTE $0xf1; BYTE $0x06
ADDQ $2, SI
less_than_2:
BTQ $0, CX
JNC done
CRC32B (SI), AX
INCQ SI
DECQ CX
JMP cleanup
done:
NOTL AX
MOVL AX, ret+32(FP)
RET
// castagnoliSSE42Triple updates three (non-inverted) crcs with (24*rounds)
// bytes from each buffer.
//
// func castagnoliSSE42Triple(
// crc1, crc2, crc3 uint32,
// a, b, c []byte,
// rounds uint32,
// ) (retA uint32, retB uint32, retC uint32)
TEXT ·castagnoliSSE42Triple(SB), NOSPLIT, $0
MOVL crcA+0(FP), AX
MOVL crcB+4(FP), CX
MOVL crcC+8(FP), DX
MOVQ a+16(FP), R8 // data pointer
MOVQ b+40(FP), R9 // data pointer
MOVQ c+64(FP), R10 // data pointer
MOVL rounds+88(FP), R11
loop:
CRC32Q (R8), AX
CRC32Q (R9), CX
CRC32Q (R10), DX
CRC32Q 8(R8), AX
CRC32Q 8(R9), CX
CRC32Q 8(R10), DX
CRC32Q 16(R8), AX
CRC32Q 16(R9), CX
CRC32Q 16(R10), DX
ADDQ $24, R8
ADDQ $24, R9
ADDQ $24, R10
DECQ R11
JNZ loop
MOVL AX, retA+96(FP)
MOVL CX, retB+100(FP)
MOVL DX, retC+104(FP)
RET
// func haveSSE42() bool
TEXT ·haveSSE42(SB), NOSPLIT, $0
XORQ AX, AX
......@@ -123,7 +205,7 @@ TEXT ·ieeeCLMUL(SB), NOSPLIT, $0
CMPQ CX, $64 // Less than 64 bytes left
JB remain64
MOVOU r2r1kp<>+0(SB), X0
MOVOA r2r1kp<>+0(SB), X0
loopback64:
MOVOA X1, X5
......@@ -165,7 +247,7 @@ loopback64:
// Fold result into a single register (X1)
remain64:
MOVOU r4r3kp<>+0(SB), X0
MOVOA r4r3kp<>+0(SB), X0
MOVOA X1, X5
PCLMULQDQ $0, X0, X1
......@@ -185,7 +267,7 @@ remain64:
PXOR X5, X1
PXOR X4, X1
// More than 16 bytes left?
// If there is less than 16 bytes left we are done
CMPQ CX, $16
JB finish
......@@ -220,7 +302,7 @@ finish:
PCLMULQDQ $0, X0, X1
PXOR X2, X1
MOVOU rupolykp<>+0(SB), X0
MOVOA rupolykp<>+0(SB), X0
MOVOA X1, X2
PAND X3, X1
......
//+build !appengine,!gccgo
// 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.
// +build !appengine,!gccgo
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 4.2
// haveSSE42 is defined in crc32_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
// castagnoliSSE42 is defined in crc32_amd64p32.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 archAvailableCastagnoli() bool {
return sse42
}
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)
func archInitCastagnoli() {
if !sse42 {
panic("not available")
}
// No initialization necessary.
}
return update(crc, IEEETable, p)
func archUpdateCastagnoli(crc uint32, p []byte) uint32 {
if !sse42 {
panic("not available")
}
return castagnoliSSE42(crc, p)
}
func archAvailableIEEE() bool { return false }
func archInitIEEE() { panic("not available") }
func archUpdateIEEE(crc uint32, p []byte) uint32 { panic("not available") }
//+build gc
// 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.
// +build gc
#define NOSPLIT 4
#define RODATA 8
......
......@@ -2,27 +2,88 @@
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// +build 386 arm arm64 ppc64 ppc64le appengine gccgo
// This file contains CRC32 algorithms that are not specific to any architecture
// and don't use hardware acceleration.
//
// The simple (and slow) CRC32 implementation only uses a 256*4 bytes table.
//
// The slicing-by-8 algorithm is a faster implementation that uses a bigger
// table (8*256*4 bytes).
package crc32
// The file contains the generic version of updateCastagnoli which does
// slicing-by-8, or uses the fallback for very small sizes.
func updateCastagnoli(crc uint32, p []byte) uint32 {
// only use slicing-by-8 when input is >= 16 Bytes
if len(p) >= 16 {
return updateSlicingBy8(crc, castagnoliTable8, p)
// simpleMakeTable allocates and constructs a Table for the specified
// polynomial. The table is suitable for use with the simple algorithm
// (simpleUpdate).
func simpleMakeTable(poly uint32) *Table {
t := new(Table)
simplePopulateTable(poly, t)
return t
}
// simplePopulateTable constructs a Table for the specified polynomial, suitable
// for use with simpleUpdate.
func simplePopulateTable(poly uint32, t *Table) {
for i := 0; i < 256; i++ {
crc := uint32(i)
for j := 0; j < 8; j++ {
if crc&1 == 1 {
crc = (crc >> 1) ^ poly
} else {
crc >>= 1
}
}
t[i] = crc
}
}
// simpleUpdate uses the simple algorithm to update the CRC, given a table that
// was previously computed using simpleMakeTable.
func simpleUpdate(crc uint32, tab *Table, p []byte) uint32 {
crc = ^crc
for _, v := range p {
crc = tab[byte(crc)^v] ^ (crc >> 8)
}
return update(crc, castagnoliTable, p)
return ^crc
}
func updateIEEE(crc uint32, p []byte) uint32 {
// only use slicing-by-8 when input is >= 16 Bytes
if len(p) >= 16 {
iEEETable8Once.Do(func() {
iEEETable8 = makeTable8(IEEE)
})
return updateSlicingBy8(crc, iEEETable8, p)
// Use slicing-by-8 when payload >= this value.
const slicing8Cutoff = 16
// slicing8Table is array of 8 Tables, used by the slicing-by-8 algorithm.
type slicing8Table [8]Table
// slicingMakeTable constructs a slicing8Table for the specified polynomial. The
// table is suitable for use with the slicing-by-8 algorithm (slicingUpdate).
func slicingMakeTable(poly uint32) *slicing8Table {
t := new(slicing8Table)
simplePopulateTable(poly, &t[0])
for i := 0; i < 256; i++ {
crc := t[0][i]
for j := 1; j < 8; j++ {
crc = t[0][crc&0xFF] ^ (crc >> 8)
t[j][i] = crc
}
}
return t
}
// slicingUpdate uses the slicing-by-8 algorithm to update the CRC, given a
// table that was previously computed using slicingMakeTable.
func slicingUpdate(crc uint32, tab *slicing8Table, p []byte) uint32 {
if len(p) >= slicing8Cutoff {
crc = ^crc
for len(p) > 8 {
crc ^= uint32(p[0]) | uint32(p[1])<<8 | uint32(p[2])<<16 | uint32(p[3])<<24
crc = tab[0][p[7]] ^ tab[1][p[6]] ^ tab[2][p[5]] ^ tab[3][p[4]] ^
tab[4][crc>>24] ^ tab[5][(crc>>16)&0xFF] ^
tab[6][(crc>>8)&0xFF] ^ tab[7][crc&0xFF]
p = p[8:]
}
crc = ^crc
}
if len(p) == 0 {
return crc
}
return update(crc, IEEETable, p)
return simpleUpdate(crc, &tab[0], p)
}
// 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.
// +build !amd64,!amd64p32,!s390x
package crc32
func archAvailableIEEE() bool { return false }
func archInitIEEE() { panic("not available") }
func archUpdateIEEE(crc uint32, p []byte) uint32 { panic("not available") }
func archAvailableCastagnoli() bool { return false }
func archInitCastagnoli() { panic("not available") }
func archUpdateCastagnoli(crc uint32, p []byte) uint32 { panic("not available") }
// 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.
// +build s390x
package crc32
const (
vxMinLen = 64
vxAlignMask = 15 // align to 16 bytes
)
// hasVectorFacility reports whether the machine has the z/Architecture
// vector facility installed and enabled.
func hasVectorFacility() bool
var hasVX = hasVectorFacility()
// 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)
}
// 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.
// +build s390x
#include "textflag.h"
// Vector register range containing CRC-32 constants
#define CONST_PERM_LE2BE V9
#define CONST_R2R1 V10
#define CONST_R4R3 V11
#define CONST_R5 V12
#define CONST_RU_POLY V13
#define CONST_CRC_POLY V14
// The CRC-32 constant block contains reduction constants to fold and
// process particular chunks of the input data stream in parallel.
//
// Note that the constant definitions below are extended in order to compute
// intermediate results with a single VECTOR GALOIS FIELD MULTIPLY instruction.
// The rightmost doubleword can be 0 to prevent contribution to the result or
// can be multiplied by 1 to perform an XOR without the need for a separate
// VECTOR EXCLUSIVE OR instruction.
//
// The polynomials used are bit-reflected:
//
// IEEE: P'(x) = 0x0edb88320
// Castagnoli: P'(x) = 0x082f63b78
// IEEE polynomial constants
DATA ·crcleconskp+0(SB)/8, $0x0F0E0D0C0B0A0908 // LE-to-BE mask
DATA ·crcleconskp+8(SB)/8, $0x0706050403020100
DATA ·crcleconskp+16(SB)/8, $0x00000001c6e41596 // R2
DATA ·crcleconskp+24(SB)/8, $0x0000000154442bd4 // R1
DATA ·crcleconskp+32(SB)/8, $0x00000000ccaa009e // R4
DATA ·crcleconskp+40(SB)/8, $0x00000001751997d0 // R3
DATA ·crcleconskp+48(SB)/8, $0x0000000000000000
DATA ·crcleconskp+56(SB)/8, $0x0000000163cd6124 // R5
DATA ·crcleconskp+64(SB)/8, $0x0000000000000000
DATA ·crcleconskp+72(SB)/8, $0x00000001F7011641 // u'
DATA ·crcleconskp+80(SB)/8, $0x0000000000000000
DATA ·crcleconskp+88(SB)/8, $0x00000001DB710641 // P'(x) << 1
GLOBL ·crcleconskp(SB), RODATA, $144
// Castagonli Polynomial constants
DATA ·crccleconskp+0(SB)/8, $0x0F0E0D0C0B0A0908 // LE-to-BE mask
DATA ·crccleconskp+8(SB)/8, $0x0706050403020100
DATA ·crccleconskp+16(SB)/8, $0x000000009e4addf8 // R2
DATA ·crccleconskp+24(SB)/8, $0x00000000740eef02 // R1
DATA ·crccleconskp+32(SB)/8, $0x000000014cd00bd6 // R4
DATA ·crccleconskp+40(SB)/8, $0x00000000f20c0dfe // R3
DATA ·crccleconskp+48(SB)/8, $0x0000000000000000
DATA ·crccleconskp+56(SB)/8, $0x00000000dd45aab8 // R5
DATA ·crccleconskp+64(SB)/8, $0x0000000000000000
DATA ·crccleconskp+72(SB)/8, $0x00000000dea713f1 // u'
DATA ·crccleconskp+80(SB)/8, $0x0000000000000000
DATA ·crccleconskp+88(SB)/8, $0x0000000105ec76f0 // P'(x) << 1
GLOBL ·crccleconskp(SB), RODATA, $144
// func hasVectorFacility() bool
TEXT ·hasVectorFacility(SB), NOSPLIT, $24-1
MOVD $x-24(SP), R1
XC $24, 0(R1), 0(R1) // clear the storage
MOVD $2, R0 // R0 is the number of double words stored -1
WORD $0xB2B01000 // STFLE 0(R1)
XOR R0, R0 // reset the value of R0
MOVBZ z-8(SP), R1
AND $0x40, R1
BEQ novector
vectorinstalled:
// check if the vector instruction has been enabled
VLEIB $0, $0xF, V16
VLGVB $0, V16, R1
CMPBNE R1, $0xF, novector
MOVB $1, ret+0(FP) // have vx
RET
novector:
MOVB $0, ret+0(FP) // no vx
RET
// The CRC-32 function(s) use these calling conventions:
//
// Parameters:
//
// R2: Initial CRC value, typically ~0; and final CRC (return) value.
// R3: Input buffer pointer, performance might be improved if the
// buffer is on a doubleword boundary.
// R4: Length of the buffer, must be 64 bytes or greater.
//
// Register usage:
//
// R5: CRC-32 constant pool base pointer.
// V0: Initial CRC value and intermediate constants and results.
// V1..V4: Data for CRC computation.
// V5..V8: Next data chunks that are fetched from the input buffer.
//
// V9..V14: CRC-32 constants.
// func vectorizedIEEE(crc uint32, p []byte) uint32
TEXT ·vectorizedIEEE(SB), NOSPLIT, $0
MOVWZ crc+0(FP), R2 // R2 stores the CRC value
MOVD p+8(FP), R3 // data pointer
MOVD p_len+16(FP), R4 // len(p)
MOVD $·crcleconskp(SB), R5
BR vectorizedBody<>(SB)
// func vectorizedCastagnoli(crc uint32, p []byte) uint32
TEXT ·vectorizedCastagnoli(SB), NOSPLIT, $0
MOVWZ crc+0(FP), R2 // R2 stores the CRC value
MOVD p+8(FP), R3 // data pointer
MOVD p_len+16(FP), R4 // len(p)
// R5: crc-32 constant pool base pointer, constant is used to reduce crc
MOVD $·crccleconskp(SB), R5
BR vectorizedBody<>(SB)
TEXT vectorizedBody<>(SB), NOSPLIT, $0
XOR $0xffffffff, R2 // NOTW R2
VLM 0(R5), CONST_PERM_LE2BE, CONST_CRC_POLY
// Load the initial CRC value into the rightmost word of V0
VZERO V0
VLVGF $3, R2, V0
// Crash if the input size is less than 64-bytes.
CMP R4, $64
BLT crash
// Load a 64-byte data chunk and XOR with CRC
VLM 0(R3), V1, V4 // 64-bytes into V1..V4
// Reflect the data if the CRC operation is in the bit-reflected domain
VPERM V1, V1, CONST_PERM_LE2BE, V1
VPERM V2, V2, CONST_PERM_LE2BE, V2
VPERM V3, V3, CONST_PERM_LE2BE, V3
VPERM V4, V4, CONST_PERM_LE2BE, V4
VX V0, V1, V1 // V1 ^= CRC
ADD $64, R3 // BUF = BUF + 64
ADD $(-64), R4
// Check remaining buffer size and jump to proper folding method
CMP R4, $64
BLT less_than_64bytes
fold_64bytes_loop:
// Load the next 64-byte data chunk into V5 to V8
VLM 0(R3), V5, V8
VPERM V5, V5, CONST_PERM_LE2BE, V5
VPERM V6, V6, CONST_PERM_LE2BE, V6
VPERM V7, V7, CONST_PERM_LE2BE, V7
VPERM V8, V8, CONST_PERM_LE2BE, V8
// Perform a GF(2) multiplication of the doublewords in V1 with
// the reduction constants in V0. The intermediate result is
// then folded (accumulated) with the next data chunk in V5 and
// stored in V1. Repeat this step for the register contents
// in V2, V3, and V4 respectively.
VGFMAG CONST_R2R1, V1, V5, V1
VGFMAG CONST_R2R1, V2, V6, V2
VGFMAG CONST_R2R1, V3, V7, V3
VGFMAG CONST_R2R1, V4, V8, V4
// Adjust buffer pointer and length for next loop
ADD $64, R3 // BUF = BUF + 64
ADD $(-64), R4 // LEN = LEN - 64
CMP R4, $64
BGE fold_64bytes_loop
less_than_64bytes:
// Fold V1 to V4 into a single 128-bit value in V1
VGFMAG CONST_R4R3, V1, V2, V1
VGFMAG CONST_R4R3, V1, V3, V1
VGFMAG CONST_R4R3, V1, V4, V1
// Check whether to continue with 64-bit folding
CMP R4, $16
BLT final_fold
fold_16bytes_loop:
VL 0(R3), V2 // Load next data chunk
VPERM V2, V2, CONST_PERM_LE2BE, V2
VGFMAG CONST_R4R3, V1, V2, V1 // Fold next data chunk
// Adjust buffer pointer and size for folding next data chunk
ADD $16, R3
ADD $-16, R4
// Process remaining data chunks
CMP R4, $16
BGE fold_16bytes_loop
final_fold:
VLEIB $7, $0x40, V9
VSRLB V9, CONST_R4R3, V0
VLEIG $0, $1, V0
VGFMG V0, V1, V1
VLEIB $7, $0x20, V9 // Shift by words
VSRLB V9, V1, V2 // Store remaining bits in V2
VUPLLF V1, V1 // Split rightmost doubleword
VGFMAG CONST_R5, V1, V2, V1 // V1 = (V1 * R5) XOR V2
// The input values to the Barret reduction are the degree-63 polynomial
// in V1 (R(x)), degree-32 generator polynomial, and the reduction
// constant u. The Barret reduction result is the CRC value of R(x) mod
// P(x).
//
// The Barret reduction algorithm is defined as:
//
// 1. T1(x) = floor( R(x) / x^32 ) GF2MUL u
// 2. T2(x) = floor( T1(x) / x^32 ) GF2MUL P(x)
// 3. C(x) = R(x) XOR T2(x) mod x^32
//
// Note: To compensate the division by x^32, use the vector unpack
// instruction to move the leftmost word into the leftmost doubleword
// of the vector register. The rightmost doubleword is multiplied
// with zero to not contribute to the intermedate results.
// T1(x) = floor( R(x) / x^32 ) GF2MUL u
VUPLLF V1, V2
VGFMG CONST_RU_POLY, V2, V2
// Compute the GF(2) product of the CRC polynomial in VO with T1(x) in
// V2 and XOR the intermediate result, T2(x), with the value in V1.
// The final result is in the rightmost word of V2.
VUPLLF V2, V2
VGFMAG CONST_CRC_POLY, V2, V1, V2
done:
VLGVF $2, V2, R2
XOR $0xffffffff, R2 // NOTW R2
MOVWZ R2, ret + 32(FP)
RET
crash:
MOVD $0, (R0) // input size is less than 64-bytes
......@@ -329,6 +329,12 @@
"revisionTime": "2016-12-15T22:53:35Z"
},
{
"checksumSHA1": "BM6ZlNJmtKy3GBoWwg2X55gnZ4A=",
"path": "github.com/klauspost/crc32",
"revision": "1bab8b35b6bb565f92cbc97939610af9369f942a",
"revisionTime": "2017-02-10T14:05:23Z"
},
{
"checksumSHA1": "8z32QKTSDusa4QQyunKE4kyYXZ8=",
"path": "github.com/patrickmn/go-cache",
"revision": "e7a9def80f35fe1b170b7b8b68871d59dea117e1",
......
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