a = (a + b + 2 * trunc(a) * trunc(b)) mod 2^(64)
        d = (d XOR a) >>> 32
        c = (c + d + 2 * trunc(c) * trunc(d)) mod 2^(64)
        b = (b XOR c) >>> 24

        a = (a + b + 2 * trunc(a) * trunc(b)) mod 2^(64)
        d = (d XOR a) >>> 16
        c = (c + d + 2 * trunc(c) * trunc(d)) mod 2^(64)
        b = (b XOR c) >>> 63