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Why Binary?

Part of the Fundamentals section of Coddy's Assembly journey — lesson 7 of 45.

Computers use electricity. But electricity is not perfect — voltage fluctuates and there is noise.

If computers tried to use 10 different voltage levels (0V, 1V, 2V... 9V) to represent digits 0-9, they would constantly make mistakes.

The solution: use only two voltage levels.

Off (0 volts) = 0
On (5V, 3.3V, or 1.8V) = 1

This is called binary. Only two symbols: 0 and 1.

Basic terms:

Bit = one binary digit (0 or 1)
Byte = 8 bits

Everything in a computer is binary:

The letter 'A' = 01000001
The number 42 = 00101010
An instruction like mov = some binary pattern

Try it yourself

This lesson doesn't include a code challenge.

Test yourself

This lesson includes a short quiz. Start the lesson to answer it and track your progress.

All lessons in Fundamentals

1The Machine

What is CPU Memory Registers vs Memory How instructions work Two-File Pattern The x86-64 Architecture

4Data Definition

The .data Section db - Define Byte dw - Define Word dd - Define Double Word dq - Define Quad Word Strings with db The $ Symbol Recap: Build data.asm

7Hello World

Planning the Program Writing data.asm

Project lesson

Writing main.asm

Project lesson

2Number Systems

Why Binary?Binary Numbers Decimal to Binary Why Hexadecimal?Hex to Decimal Decimal to Hex ASCII & Hex

5Exit Syscall

What is Syscall?Exit Syscall (60)Exit Codes Recap: Clean Exit

3First instruction - MOV

What is MOV?MOV Immediate MOV Register to Register MOV Memory to Register MOV Register to Memory LEA - Load Address MOV with Different Sizes Practice: Swap Registers Recap: MOV Challenge

6Write Syscall

Write Syscall (1)File Descriptor (rdi)Buffer Address (rsi)Byte Count (rdx)Putting It Together Printing Two Strings Newline Matters Recap: Write Setup