Practical uses
- Inspect what compilers and CPUs actually execute
- Optimize tiny performance-critical routines
- Program bootloaders and embedded targets
- Reverse engineer binaries and debug crashes
Assembly
The human-readable form of the instructions a CPU actually runs.
Assembly language is a thin layer above raw machine code. Every other programming language compiles down to this. Learning it means seeing exactly what the CPU does — registers, memory, jumps, the stack. It takes more code to do simple things, but it shows you what every other language is doing underneath. We teach x86-64 NASM on Linux, the most common flavor for desktop/server work.
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Start lesson 1 Lessons
- How CPUs Actually WorkBefore writing any code, you'll build a simple picture of how a CPU runs a program: registers, memory, and the fetch-decode-execute cycle. The rest of the track builds on this.
- Hello, World!You'll write, assemble, link and run a program that prints Hello, World!. Along the way you'll see the system call that higher-level languages normally hide from you.
- Registers & Data MovementYou'll learn `mov`, the most common instruction, which copies data between registers and memory (the source is left unchanged). Nearly every program you write will use it.
- Arithmetic & LogicYou'll learn the instructions for arithmetic and bitwise operations, and how each result updates the FLAGS register. Those flags are what conditional jumps use to make decisions.
- Control Flow & LoopsAssembly has no if/else or for loops, only jumps. You'll learn how to build conditions and loops from `jmp`, `cmp` and the conditional jumps.
- The Stack & FunctionsYou'll learn how the stack holds return addresses and local variables, and how `push`, `pop`, `call` and `ret` work together. This is how function calls and recursion work at the machine level.
- System CallsA system call is how a program asks the kernel to do something for it, such as reading a file or writing to the terminal. You'll learn the x86-64 Linux convention for making syscalls and use several common ones.
- Calling C Functions from ASMYou'll learn how to call C library functions such as printf and malloc from assembly. This lets you reuse existing code and keep assembly for the parts that need it.
- Mini Project: String OperationsYou'll write a small set of string functions in plain assembly without libc: strlen, strcpy, strcmp and a number-to-string converter. It brings together registers, memory access, loops and functions.
- x86-64 Assembly CheatsheetRegisters, instructions, and calling convention on one page.
Install it on your own computer
This track uses NASM (the Netwide Assembler) and the x86-64 Linux calling conventions, so you need a Linux environment. On Windows, WSL2 works well; on macOS, a Linux VM or container is the simplest option.
# Install WSL2 (run in PowerShell as Administrator):
wsl --install
# Restart, then in Ubuntu (WSL2):
sudo apt update && sudo apt install nasm build-essential
# Verify:
nasm --version
ld --versionWhat people build with Assembly
Learn the basics first, then pick up these tools when a project needs them.
Projects to try
- Hello world syscall
- Integer conversion routine
- Boot sector
- SIMD image-processing kernel