MHR Hash

public static class MHRHash
    {
        private const uint m_seed = 0xffffffff;
        private const uint m_c1 = 0xcc9e2d51;
        private const uint m_c2 = 0x1b873593;
        private const uint m_c3 = 0xfaddaf14;
        private const int m_r1 = 15;
        private const int m_r2 = 13;
        public  static int Hash(byte[] data)
        {
            if (data.Length % 4 != 0) throw new InvalidDataException($"{nameof(data)} is not 4 byte aligned.");

            int hashPosition = data.Length - 4;

            uint hash = m_seed;
            for (int i = 0; i < ((data.Length - 4) / 4); i++)
            {
                uint intData = BitConverter.ToUInt32(data, i * 4);
                uint eax = intData * m_c1;
                uint ecx;

                eax = rol32(eax, m_r1);
                ecx = eax * m_c2;

                hash ^= ecx;
                hash = rol32(hash, m_r2);
                hash += m_c3;

                long temp = hash + hash * 4;
                hash = (uint)temp;
            }

            byte twoBits = data[hashPosition];
            uint extraHash = 0;

            if (twoBits == 3)
            {
                extraHash = (uint)data[hashPosition + 2] << 0x10;
            }

            if (twoBits == 2)
            {
                extraHash = (uint)data[hashPosition + 1] << 8;
            }

            if (twoBits == 1)
            {
                extraHash = data[hashPosition] ^ extraHash;
                extraHash *= m_c1;
                extraHash *= m_c2;
                hash ^= extraHash;
            }

            hash ^= (uint)hashPosition;
            hash ^= hash >> 16;
            hash *= 0x85ebca6b;
            hash ^= hash >> 13;
            hash *= 0xc2b2ae35;
            hash ^= hash >> 16;

            return (int)hash;
        }

        private static uint rol32(uint value, int amount)
        {
            return (value << amount) | (value >> (32 - amount));
        }
    }