Learn: The ALU - Arithmetic vs Logic

Welcome!You've already learned about why the CPU is essential, the fetch-decode-execute cycle, and what registers do. Now, let's dive into the Arithmetic Logic Unit (ALU) and explore its crucial role in performing calculations and logical operations within the CPU.

What is the ALU?The Arithmetic Logic Unit (ALU) is a key component of the CPU. It performs arithmetic operations (like addition and subtraction) and logical operations (like comparing values or checking conditions). Without the ALU, the CPU wouldn't be able to process data effectively.

Arithmetic OperationsThe ALU can handle simple calculations like addition, subtraction, multiplication, and division. For example, when you use a calculator app, it's the ALU in your device's CPU handling those operations.

Logical OperationsIn addition to arithmetic, the ALU performs logical operations. These include comparisons (e.g., checking if one value is greater than another) and Boolean logic (e.g., AND, OR, NOT). Logical operations help the CPU make decisions during program execution.

How the ALU WorksThe ALU takes input from the CPU's registers, processes the data (either performing a calculation or a comparison), and then outputs the result to another register. This process happens at incredible speeds to execute instructions efficiently.

Real-World Example: Using the ALUImagine you're creating a spreadsheet. When you add two cells together, the ALU performs the addition. If you use a formula like =IF(A1 > B1), the ALU is comparing the values in those cells to decide what to do next.

Review Time!Great work! You've learned about the ALU, the difference between arithmetic and logical operations, and how the ALU interacts with registers. Let’s test your understanding with a few final questions.