Phase One

Start by building an $8-$bit ALU using Logisim. This ALU can implement $16$ instructions on $8-$bit operands. In previous lessons, you created a $4-$bit ALU; this will be $8-$bit, and you should adjust$/$add components accordingly.

We would suggest the following minimum list of instructions:

Arithmetic addition

Increment

Decrement

Comparison $($with $3$ outputs: one for equals, one for less than and one for greater than$)$

Logic bitwise Not

Logic bitwise And

Logic bitwise Or

Register right logic shift

Register left logic shift

In addition to these nine instructions, please suggest five more instructions that the ALU can implement for a total of $14$ instructions $($we are reserving $2$ instructions for branching$).$ Justify the importance of the five instructions you added in a Word doc to submit as part of this assignment. Label these instructions as 'Phase One.$\text{'}$

After you've suggested and justified your five suggested instructions, please build at least the nine above$-$mentioned operations as blocks in Logisim.

Phase Two

In phase two of the project, you are required to design the instruction set of the ALU$/$CPU as follows:

Create the opcode table for the ALU by giving a binary code and a name for each instruction you built in Logisim in phase one.

Decide how many operands you want your instructions to handle and justify your choice. We suggest either one operand with accumulator or two operands with the result stored in one of the input registers.

$($this is the part I need help with$)$ In Logisim, add a multiplexer to the circuit you built in phase one that chooses one of the available operations. The simplest way to create this part of the CPU is to connect the outputs of the multiplexer to the inputs of AND arrays connected to the output of the operation blocks.