This is my 4 bit test ALU.
It has 6 functions, Add with carry, Subtract with carry, Shift Right with carry fill, AND, OR, and XOR.
While assembling the ALU I made some errors two of them being with the adder carry chain being wired backwards (MSB to LSB)
And the same with the shifter; wired to left shift instead of right shift.
It uses 181 transistor's and I am currently constructing the full 8 bit ALU which will contain 346 transistor's.
A photograph with labels:
The small Mux is to select the carry out from ether the adder, shifter, or the carry In.
The inverter mux selects between invert or pass (used to select subtraction/addition).