J-type immediate transformation:
    # ADDDDDDDCBBBBBBBBBB     ABBBBBBBBBBCDDDDDDDD
    # 11111111111111110000 -> 11111111000111111111
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B-type immediate transformation:

    # ADBBBBBBCCCC         ABBBBBB CCCCD
    # 1111111101000   ->   1111111 01001
