opcode         address 1               address 2        register
|x x x x|x x x x x x x x x x x x|x x x x x x x x x x x x|x x x x|

 opcode1  ID     opcode2                  address        register
|0 0 0 0|0 1|x x x x x x x x x x|x x x x x x x x x x x x|x x x x|

 opcode1  ID    opcode2                       unused
|0 0 0 0|0 0|x x x x x x x|x x x x x x x x x x x x x x x x x x x|