Learning Assembly by Solving

Welcome to Learning Assembly by Solving, a collection of 20 small assembly language programs designed to teach fundamental concepts through practical examples. Each program solves a specific problem, ranging from basic arithmetic to control structures, all written in x86-64 assembly using NASM syntax for Linux systems.

Purpose

The goal is to learn assembly language by implementing solutions to common programming problems. Each .S file (e.g., 1.S, 2.S, ..., 20.S) in the root directory corresponds to a question listed below, providing hands-on experience with low-level programming.

Questions and Solutions

Here’s the list of problems solved in this repository:

1. Check if a number is even or odd
   Determines the parity of a number using bitwise operations.

2. Find the maximum of two numbers
   Compares two numbers and outputs the larger one.

3. Compare two numbers and print "Equal" if they're equal
   Checks equality and prints a message accordingly.

4. Add two numbers and print the result
   Performs addition and displays the sum as a character/digit (for small results).

5. Subtract two numbers and print the result
   Computes the difference and outputs it.

6. Count from 1 to 5 and print each number on a new line
   Uses a loop to print numbers sequentially.

7. Print the factorial of 5
   Calculates 5! (120) and displays it.

8. Sum the numbers from 1 to 10
   Adds numbers in a range and prints the total (55).

9. Check if a number is a multiple of 3
   Tests divisibility by 3 and outputs the result.

10. Print the first 5 even numbers
    Lists 0, 2, 4, 6, 8 with a loop.

11. Reverse a 2-digit number (e.g., 42 → 24)
    Swaps the digits of a two-digit number.

12. Convert a single digit (0-9) to ASCII and print it
    Transforms a digit to its ASCII character for output.

13. Print "Positive" or "Negative" based on a signed number
    Determines the sign of a number and prints the appropriate label.

14. Calculate and print 2^n for small n (like 0–5)
    Computes powers of 2 (1, 2, 4, 8, 16, 32) and displays them.

15. Check if a number is prime (try for small ones like 2–10)
    Tests primality for small integers.

16. Store 5 numbers in memory and find their sum
    Sums an array of 5 numbers.

17. Swap two variables using a temporary register
    Exchanges the values of two variables.

18. Find the average of 3 numbers
    Calculates the integer average of three numbers.

19. Print the alphabet A to E using a loop
    Outputs A, B, C, D, E on separate lines.

20. Take two numbers and print which one is closer to 10
    Compares distances from 10 and prints the result.

Files

The repository contains 20 assembly source files in the root directory:

• 1.S, 2.S, 3.S, ..., 20.S

Each file corresponds to the question number above and contains a standalone program written in x86-64 assembly.

How to Run

To compile and execute these programs on a Linux system with NASM installed:

1. Assemble:

   nasm -f elf64 <filename>.S -o <filename>.o

   Example: nasm -f elf64 1.S -o 1.o

2. Link:

ld <filename>.o -o <filename>

Example: ld 1.o -o 1

3. Run:

./<filename>

Example: ./1

Prerequisites

• NASM: The Netwide Assembler (install with sudo apt install nasm on Ubuntu/Debian).
• Linux: These programs target x86-64 Linux systems using system calls (e.g., write, exit).

Or try online compilers such as https://onecompiler.com/assembly/43dsexwn3

Contributing

Feel free to fork this repository, submit pull requests, or open issues for suggestions and improvements. Contributions are welcome!

Acknowledgments

Created as a learning exercise by Max Base to explore assembly language programming. Inspired by fundamental programming challenges adapted to the low-level environment.

License

Copyright © 2025 Max Base. This project is licensed under the MIT License.