Bitshifting bytes to form a long var fails!

Using Arduino Programming Questions
43

To nick gammon

union ByteToLong
{
    struct
    {
      byte a1: 4;
      byte a2: 4;
      byte b1: 4;
      byte b2: 4;
      byte c1: 4;
      byte c2: 4;
      byte d1: 4;
      byte d2: 4;
    } nybble;
    unsigned long whole;
};

The wrong output is

8000
8010

The correct is

8000
8002
8004
8006
8008
8010

If you put the code snippet that i posted in a sketch and call it:

ReadData(8000, 8010);

you will get the output!

I will try the mods from dhenry!