Gate$-$level schematic for the final ALU design.

Create a table with three columns: $c_0,c_1$ and $OP,$ such that $c_0$ and $c_1$ correspond to the ALU control

signals and OP is the operation it will perform, like AND$\mathrm{.}3\mathrm{.}34-$bit ALU Design

At this point, we have acquired all pieces we need to finish our simple ALU design which can do three operations: AND, addition and subtraction. Our last job is signal connection.

Figure $7$: Simple ALU Design

Figure $7$ is the block design diagram of our ALU. $c_0$ is the signal that selects AND or math function. $c_1$ is the signal that determines addition or subtraction. Note that there is a black box in Figure $7,$ which is the unit to detect overflow. We will use it later.