2. Stack Stack Pointer A stack is a means of storing data that works on a ‘Last in first out’ (LIFO) basis. It reverses the order that data arrives and is sent.

3. Program Counter Instruction 5 Instruction 4 Instruction 3 Instruction 2 Instruction 1 Program Counter Points to the next instruction that needs to be fetched and executed.

4. positive number negative number overflow result zero Status Register The status register holds condition codes to indicate the outcome of operations. For example, an arithmetic operation may produce a positive, negative, zero or overflow result, so a flag is set accordingly.

5. Accumulator Control Unit Holds the result of the current set of instructions. For example, ADD #45 which means add the number 45 to the current contents in the accumulator and store the result in the accumulator. Arithmetic Logic Unit (ALU)

6. Current Instruction Instruction 4 Instruction 3 Instruction 2 Instruction 1 Current Instruction Current Instruction Register Holds the current instruction to be executed while it is decoded and executed.

7. Address Data # This holds the address of the memory location currently being accessed by the processor. It stores memory addresses of instructions and data.

8. Data # The control unit is a component of a computer's central processing unit (CPU) that directs operation of the processor. It tells the computer's memory, arithmetic/logic unit and input and output devices how to respond to a program's instructions.

9. Data # This holds the data being transferred to and from memory and currently being acted upon by the processor.

10. Instructions & Data Arithmetic Logic Unit (ALU) An arithmetic logic unit(ALU) is a digital circuit that performs integer arithmetic and logical operations. The ALU is a fundamental building block of the central processingunit of a computer, and even the simplest microprocessors contain one for purposes such as maintaining timers.