israellot

public static unsafe uint ChecksumExpertAvx2(ReadOnlySpan<byte> arr)
{
        ref byte refSpan = ref MemoryMarshal.GetReference<byte>(arr);

        var z = 0;
        uint sum = 0;

        var vectorSum = Avx2.Xor(Vector256<byte>.Zero, Vector256<byte>.Zero).AsUInt32();
        var mask = Vector256.Create((byte)3, 2, 1, 0, 7, 6, 5, 4, 11, 10, 9, 8, 15, 14, 13, 12, (byte)3, 2, 1, 0, 7, 6, 5, 4, 11, 10, 9, 8, 15, 14, 13, 12);

israellot

public unsafe static uint ChecksumHacker(ReadOnlySpan<byte> arr)
{
    if (arr.Length == 0) return 0;

    fixed (byte* ptr = arr)
    {
        uint sum0 = 0, sum1 = 0, sum2 = 0, sum3 = 0;
        uint z = 0;

        ulong tmp0 = 0, tmp1 = 0;

israellot

public static unsafe uint ChecksumExpert(ReadOnlySpan<byte> arr)
{
    if (arr.Length == 0) return 0;

    fixed (byte* ptr = arr)
    {
        uint sum = 0;
        int z = 0;

        var limit = arr.Length - 32;

israellot

public static unsafe uint ChecksumExpertAvx(ReadOnlySpan<byte> arr)
{
        ref byte refSpan = ref MemoryMarshal.GetReference<byte>(arr);

        uint z = 0;            
        uint sum = 0;
        
        var vectorSum = Avx.Xor(Vector128<byte>.Zero, Vector128<byte>.Zero).AsUInt32();  
        var mask = Vector128.Create((byte)3, 2, 1, 0, 7, 6, 5, 4, 11, 10, 9, 8, 15, 14, 13, 12);

israellot

public static unsafe uint Checksum(ReadOnlySpan<byte> arr)
{
    if (arr.Length == 0) return 0;

    fixed (byte* ptr = arr)
    {
        uint sum = 0;
        int z = 0;

        var limit = arr.Length - 4;

israellot

// Compute a 32-bit big-endian checksum on arr
public static uint Checksum(ReadOnlySpan<byte> arr)
{
    if (arr.Length == 0) return 0;

    uint sum0 = 0, sum1 = 0, sum2 = 0, sum3 = 0;

    for(var i = 0; i<arr.Length; i++)
    {
        switch (i % 4)

israellot

public unsafe static uint ChecksumHackerExpanded(ReadOnlySpan<byte> arr)
{
    if (arr.Length == 0) return 0;

    fixed (byte* ptr = arr)
    {
        uint sum0 = 0, sum1 = 0, sum2 = 0, sum3 = 0;
        uint z = 0;
        int rem = arr.Length % 32;

israellot

public unsafe static uint ChecksumExpert(ReadOnlySpan<byte> arr)
{
    if (arr.Length == 0) return 0;

    fixed (byte* ptr = arr)
    {
        uint sum0 = 0, sum1 = 0, sum2 = 0, sum3 = 0;
        uint z = 0;
        int rem = arr.Length % 32;

israellot

public static unsafe int PointerAccessInt(byte* ptr,int x,int y)
{
   return ptr[x]& ptr[x+y];
}

public static unsafe int PointerAccessUInt(byte* ptr,uint x,uint y)
{
   return ptr[x]& ptr[x+y];
}

israellot

public class CrcBenchmark
{
    public byte[]? SourceBytes { get; set; }

    [Params(1_000_000)]
    public int Length { get; set; }

    [GlobalSetup]
    public void Setup()
    {