// using this polynomial.
var castagnoliTable *Table
var castagnoliTable8 *slicing8Table
var updateCastagnoli func(crc uint32, p []byte) uint32
var castagnoliOnce sync.Once
var haveCastagnoli atomic.Bool

func castagnoliInit() {
	castagnoliTable = simpleMakeTable(Castagnoli)

	if archAvailableCastagnoli() {
		archInitCastagnoli()
		updateCastagnoli = archUpdateCastagnoli
	} else {
		// Initialize the slicing-by-8 table.

func archInitCastagnoli() {
	if !cpu.X86.HasSSE42 {
		panic("arch-specific Castagnoli not available")
	}
	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++ {