|        a         |        b         |        c         |        d         | sel  |       out        |
| 0000000000000000 | 0000000000000000 | 0000000000000000 | 0000000000000000 |  00  | 0000000000000000 |
| 0000000000000000 | 0000000000000000 | 0000000000000000 | 0000000000000000 |  01  | 0000000000000000 |
| 0000000000000000 | 0000000000000000 | 0000000000000000 | 0000000000000000 |  10  | 0000000000000000 |
| 0000000000000000 | 0000000000000000 | 0000000000000000 | 0000000000000000 |  11  | 0000000000000000 |
| 0001001000110100 | 1001100001110110 | 1010101010101010 | 0101010101010101 |  00  | 0001001000110100 |
| 0001001000110100 | 1001100001110110 | 1010101010101010 | 0101010101010101 |  01  | 1001100001110110 |
| 0001001000110100 | 1001100001110110 | 1010101010101010 | 0101010101010101 |  10  | 1010101010101010 |
| 0001001000110100 | 1001100001110110 | 1010101010101010 | 0101010101010101 |  11  | 0101010101010101 |