L2 Low Level Programming

Key Terms

• Little Man Computer (LMC) – A model that helps us understand how simple CPUs work.

• Accumulator – A special register that holds numbers during calculations.

• Instruction – A single command the computer can follow (e.g., INP, ADD, STA).

• Memory Address – Where numbers or instructions are stored.

• Branching – Making the program jump to a different part based on a condition.

What is the Little Man Computer (LMC)?

LMC is like a classroom role-play: imagine a tiny person (the "Little Man") in a post office with drawers. He follows your instructions, one step at a time. These instructions include getting numbers, adding them, storing them, or checking if they’re zero.

Why Learn Low-Level Programming?

• It helps you understand how computers really think.

• It shows you what goes on behind the scenes of Python or Scratch.

• It’s great for controlling small devices with limited memory.

Example Program: Add Two Numbers

This program takes two inputs and adds them together. It stores the first number in memory (FIRST), then adds it to the second input and outputs the result.

INP        // Get first number

STA FIRST

INP        // Get second number

ADD FIRST

OUT        // Show result

HLT        // Stop

FIRST DAT

Real-World Example

Imagine a vending machine: it needs to check how much money was inserted, add credit, and decide what button was pressed. These small steps are just like LMC instructions!

Common Mistakes to Avoid

🚫 Mistake: Forgetting to store or load values correctly. ✅ Tip: Use comments in your LMC to explain what each line does.