Pre-Execution state of Register/Memory Location values:

PC: 35

Memory Location	Value
35	901 (INPUT) [Assume user inputs 500 from keyboard]
36	181 (ADD 81)
37	383 (STORE 83)
38	901 (INPUT) [Assume user inputs 901 from keyboard]
39	583 (SUBTRACT 83)
40	902 (OUTPUT A)
41	HALT
81	400
82	000
83	000

* Note: 901 and 902 are instruction for input and output contents of Accumulator.

The following code is executed. Compute the result. Show the values of the registers in each of the following step. Mark Fetch/Execute Cycles within the code. Write a summary on what this program does.

Instruction: 901 (Input)

PC -> MAR MDR -> IR IOR -> A

PC+1 -> PC

Instruction: ADD 81

PC -> MAR MDR -> IR

IR[address] -> MAR

A+MDR -> A

PC +1 -> PC

Instruction: STORE 83

PC -> MAR MDR -> IR IR[address] -> MAR

A -> MDR PC+1 -> PC

Instruction: 901 (Input)

PC -> MAR MDR -> IR IOR -> A

PC+1 -> PC

Instruction: SUBTRACT 83

PC -> MAR MDR -> IR

IR[address] -> MAR

A-MDR -> A

PC+1 -> PC

Instruction: 902 (OUTPUT A)

PC -> MAR MDR -> IR

A -> IOR

PC+1 -> PC

// This is the halt instruction. Assume the content on that memory location is HALT and the system knows to halt the program when that instruction is loaded.

PC -> MAR MDR -> IR

WHAT IS DISPLAYED AS THE FINAL ANSWER? __________