Learn: The ALU - Arithmetic vs Logic

Welcome!Welcome back! You've already learned about the CPU, the fetch-decode-execute cycle, and the role of registers. Now, let's dive into the Arithmetic Logic Unit (ALU), an essential part of the CPU.

What is the ALU?The Arithmetic Logic Unit (ALU) is a critical part of the CPU. It performs mathematical operations, like addition and subtraction, and logical operations, such as AND, OR, and NOT. These operations are key to helping the CPU process data and make decisions.

Arithmetic OperationsArithmetic operations involve calculations, like addition, subtraction, multiplication, and division. For example, when you add two numbers together in a program, the ALU carries out the calculation.

Logic OperationsLogic operations involve comparing values and deciding based on conditions. Common operations include AND (both conditions must be true), OR (at least one condition must be true), and NOT (reverses a condition). These operations are vital for decision-making in programs.

Why Is the ALU Important?The ALU is the 'workhorse' of the CPU, handling the calculations and comparisons needed to run programs. Without it, the CPU couldn't process complex instructions or respond to conditions in code.

How Arithmetic and Logic Work TogetherWhile arithmetic handles calculations, logic operations help make decisions based on those results. For example, the ALU might calculate a total and then use logic to check if it exceeds a certain threshold.

Review Time!Great work! You've learned how the ALU handles arithmetic and logic operations. Let’s test your understanding with a few questions.