for len(p) > 8 {
			crc ^= byteorder.LeUint32(p)
			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 simpleUpdate(crc, &tab[0], p)

		}
		// Update using slicing-by-8
		for len(p) > 8 {
			crc ^= byteorder.LeUint64(p)
			crc = helperTable[7][crc&0xff] ^
				helperTable[6][(crc>>8)&0xff] ^
				helperTable[5][(crc>>16)&0xff] ^
				helperTable[4][(crc>>24)&0xff] ^
				helperTable[3][(crc>>32)&0xff] ^
				helperTable[2][(crc>>40)&0xff] ^
				helperTable[1][(crc>>48)&0xff] ^
				helperTable[0][crc>>56]
			p = p[8:]
		}
	}

	// 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),

// 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)
}

// 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

		aligned := len(p) & ^vecAlignMask
		crc = vectorCrc32(crc, crcCast, p[:aligned])
		p = p[aligned:]
	}
	if len(p) == 0 {
		return crc
	}
	return ppc64SlicingUpdateBy8(crc, archCastagnoliTable8, p)
}

func archAvailableIEEE() bool {
	return true
}
func archAvailableCastagnoli() bool {
	return true
}

var archIeeeTable8 *slicing8Table

func archInitIEEE() {

	}
	d.crc = byteorder.BeUint32(b[8:])
	return nil
}

func update(crc uint32, tab *Table, p []byte, checkInitIEEE bool) uint32 {
	switch {
	case haveCastagnoli.Load() && tab == castagnoliTable:
		return updateCastagnoli(crc, p)
	case tab == IEEETable:
		if checkInitIEEE {
			ieeeOnce.Do(ieeeInit)
		}
		return updateIEEE(crc, p)
	default:
		return simpleUpdate(crc, tab, p)

package crc32

import "internal/cpu"

func castagnoliUpdate(crc uint32, p []byte) uint32
func ieeeUpdate(crc uint32, p []byte) uint32

func archAvailableCastagnoli() bool {
	return cpu.ARM64.HasCRC32
}

func archInitCastagnoli() {
	if !cpu.ARM64.HasCRC32 {
		panic("arch-specific crc32 instruction for Castagnoli not available")
	}
}

func archUpdateCastagnoli(crc uint32, p []byte) uint32 {
	if !cpu.ARM64.HasCRC32 {

// license that can be found in the LICENSE file.

#include "textflag.h"

// castagnoliUpdate updates the non-inverted crc with the given data.

// func castagnoliUpdate(crc uint32, p []byte) uint32
TEXT ·castagnoliUpdate(SB),NOSPLIT,$0-36
	MOVWU	crc+0(FP), R9  // CRC value
	MOVD	p+8(FP), R13  // data pointer
	MOVD	p_len+16(FP), R11  // len(p)

update:
	CMP	$16, R11
	BLT	less_than_16

  }

  private static int referenceCrc(byte[] bytes) {
    int crc = ~0;
    for (byte b : bytes) {
      crc = (crc >>> 8) ^ Crc32cHashFunction.Crc32cHasher.BYTE_TABLE[(crc ^ b) & 0xFF];
    }
    return ~crc;
  }

  /**
   * Verifies that the crc of an array of byte data matches the expected value.
   *
   * @param expectedCrc the expected crc value.
   * @param data the data to run the checksum on.
   */