The basic structure of a ROM :
This structure shows that every function has some mapping and for corresponding high value they output one.
All four function depends on $3$ variables and therefore table will look like this :
| x |
y |
z |
A |
B |
C |
D |
| 0 |
0 |
0 |
0 |
1 |
0 |
1 |
| 0 |
0 |
1 |
1 |
1 |
0 |
1 |
| 0 |
1 |
0 |
1 |
0 |
1 |
1 |
| 0 |
1 |
1 |
0 |
0 |
0 |
1 |
| 1 |
0 |
0 |
1 |
0 |
0 |
0 |
| 1 |
0 |
1 |
0 |
0 |
0 |
1 |
| 1 |
1 |
0 |
1 |
1 |
1 |
0 |
| 1 |
1 |
1 |
0 |
1 |
0 |
1 |
