lc3.fun

Master assembly programming from the ground up with interactive lessons, a built-in simulator, and hands-on projects.

Start Learning Open Simulator

19

Interactive Lessons

15

Coding Projects

15

LC-3 Instructions

Curriculum

Foundations

Welcome to LC-3

Introduction to the LC-3 architecture and why we learn assembly.

Binary, hexadecimal, and two's complement representation.

Registers & Memory

Understanding registers, memory layout, and the fetch-execute cycle.

Instructions

The arithmetic and logical operate instructions.

NOT & Subtraction

Bitwise NOT and how to subtract without a SUB instruction.

Memory & Data

PC-relative addressing and loading effective addresses.

LDR, STR, LDI & STI

Base+offset and indirect addressing modes.

Control Flow

Conditional and unconditional branches using condition codes.

Implementing while loops and for loops with branches.

Unconditional jumps and subroutine calls.

I/O & TRAP

TRAP Routines & I/O

System calls for input and output.

Subroutines

Subroutines & the Stack

Writing reusable functions with proper register saving.

Problem Solving

Common Patterns & Idioms

The reusable building blocks you'll combine to solve any LC-3 problem.

Translating Algorithms to LC-3

A step-by-step method for turning any algorithm into working LC-3 code.

Advanced

Implementing recursive functions in LC-3 assembly.

String Processing

Working with strings: length, comparison, and manipulation.

Data Structures

Implementing linked lists and stacks in LC-3.

Bit Manipulation

Advanced bit tricks with only AND, NOT, and ADD.

Sorting Algorithms

Implementing bubble sort in LC-3 assembly.

Projects

Fibonacci Sequence

Advanced—Compute and print the first N Fibonacci numbers.

Advanced—Sort an array of single-digit numbers and print them in order.

Reverse String In Place

Advanced—Reverse a null-terminated string in memory.

Binary to Decimal

Advanced—Convert a binary string to its decimal value.

Advanced—Remove all spaces from a string in place.

Palindrome Checker

Advanced—Check if a null-terminated string is a palindrome, ignoring spaces.

Intermediate—Sum the elements of an array and print the result.

Character Counter

Intermediate—Count occurrences of a character in a string.

Intermediate—Count the number of vowels in an uppercase string.

Multiply Subroutine

Intermediate—Write a subroutine that multiplies two numbers.

Intermediate—Find the maximum value and its index in an array.

Beginner—Print "Hello, World!" to the console.

Beginner—Read a character and print it back 5 times.

Beginner—Print a countdown from 9 to 0.

Beginner—Find the length of a null-terminated string in memory.