Modular 4-bit Minecraft Computer

Features:
64 bits of 4-bit wide memory
Modular system

Current instruction set:
0: NULL
1: ADD <INT> <INT>
2: SUB <INT> <INT>
3: RAN (randomly picks either 1 or 0)
4: AND <INT> <INT>
5: XOR <INT> <INT>
6: OR <INT> <INT>
7: WRITE (writes to ram) <Address> <INT>
8:
9:
A:
B:
C:
D:
E:
F:

There are 3 modes for input, pure INT (just giving a number) address (gets the value from an address) and register (gets the value of the last output). When I say <INT> in the instruction set that is just a guidline, it has nothing to do with the input mode.

Planned things:
Ability to get values from memory
Reading from ROMs
BIOS video interrupt