Where are x86 assembly skills useful.

ChatGPT to the rescue:

x86 assembly skills are useful in a variety of fields—especially those that require low-level control over hardware, deep performance optimizations, or reverse engineering. Here’s a breakdown of where and why x86 assembly is valuable:

🛠️ 1. Systems Programming​

  • Why it’s useful: Understanding how software interacts with hardware.
  • Applications:
    • Writing or modifying operating systems (e.g., bootloaders, kernels).
    • Developing embedded systems (though ARM is more common there now).
    • Creating low-level utilities (e.g., memory managers, interrupt handlers).

💣 2. Reverse Engineering​

  • Why it’s useful: Software is often distributed in compiled form (binaries), and reading machine instructions is necessary to understand it.
  • Applications:
    • Malware analysis and cybersecurity.
    • Game modding or hacking.
    • Cracking or bypassing software protection mechanisms.
    • Analyzing legacy code without source.

🧪 3. Exploit Development & Security Research​

  • Why it’s useful: Vulnerabilities often occur at the assembly/machine-code level.
  • Applications:
    • Writing buffer overflow and ROP chain exploits.
    • Analyzing shellcode or crafting custom payloads.
    • Participating in Capture The Flag (CTF) competitions.

🚀 4. Performance Optimization​

  • Why it’s useful: You can squeeze out the last drops of performance when compilers fall short.
  • Applications:
    • Hand-tuning hot loops in graphics engines or DSP algorithms.
    • Writing SIMD code (e.g., with SSE/AVX instructions).
    • Optimizing compilers, game engines, or scientific computing libraries.

🖥️ 5. Emulator and Virtual Machine Development​

  • Why it’s useful: Emulators need to understand and possibly translate machine instructions.
  • Applications:
    • Writing emulators for old x86 systems.
    • Building virtual machines or hypervisors.
    • Implementing dynamic binary translation systems (e.g., QEMU, DOSBox).

🔧 6. Compiler and Toolchain Development​

  • Why it’s useful: Compilers generate assembly; tools like debuggers, disassemblers, and profilers analyze it.
  • Applications:
    • Backend development for compilers (e.g., LLVM, GCC).
    • Creating or extending disassemblers and debuggers (e.g., Ghidra, IDA Pro).
    • Writing binary instrumentation or profiling tools.

🧓7. Legacy Systems and Industrial Applications​

  • Why it’s useful: Many old systems still run on x86 and are difficult or impossible to replace.
  • Applications:
    • Maintaining legacy enterprise software.
    • Reverse engineering old hardware drivers.
    • Working with industrial control systems or medical devices.

🧑‍🏫 8. Education and Understanding Computer Architecture​

  • Why it’s useful: Teaches how the CPU actually works.
  • Applications:
    • Teaching CS students about CPU internals, stack frames, memory layout, etc.
    • Writing simulators or teaching tools for instruction-level understanding.

🎮 Niche: Game Hacking / Cheat Development​

  • Why it’s useful: Games are usually compiled binaries; hacking them requires binary patching, memory scanning, and injection.
  • Applications:
    • Developing trainers, cheats, or mod loaders.
    • Creating bots or AI agents that manipulate game memory.

Should You Learn x86 Assembly?​

  • Yes, if you're:
    • Interested in security, OS dev, or reverse engineering.
    • A CS student who wants to understand what compilers really do.
    • Working with performance-critical or legacy software.
  • Maybe not, if you're:
    • Focused only on web or high-level app development.
Click to expand...
 
If OP wants to contribute to FreeBSD development, a good place to start is by reading the FreeBSD Developer's Handbook... But if OP also wants to practice x86/64 asm coding, the Developer's Handbook can tell OP how useful that skill is - because most of the hardware drivers for FreeBSD are actually written in C.

IIRC, assembler is the language of choice for writing compilers like cc, GCC, and LLVM. It's probably not impossible to write something for an AMD GPU or for a Pi breadboard, but you gotta have skills, patience, and enough of an incentive actually secured to be motivated do that.
 
There is a big difference between asm for the kernel, asm for userland programming, and specialized userland.

Userland programming uses common instructions and can be learned by looking at the output of compilers. Not that much point to it, you won't be the compiler by much with common instructions

In the kernel you often use highly specialized instructions to set up obscure things that you do nowhere else.

Then there is optimization via SIMD instructions. This is highly rewarding but still unportable code and pretty challenging. It has very little overlap with the other two. If you are interested in this, FreeBSD is making pushes in this direction.
 
A fun way to learn x86 assembly is cracking software. OllyDbg on Windows, radare2 on *nix. Both support patching. (I find IDA Pro too heavy)

Last thing I cracked was probably Builder Xcessory Pro (a nifty Motif GUI builder) for digital preservation purposes.

Cracking aside, if you are looking at greenfield development, a more rewarding and immediate environment for assembly is probably MS-DOS (i.e DOSBox). Everything is just so much more accessible and there are more books, tools and community to write fun software.
 
I wrote an EXIF decoder as a class unit for Delphi.

Parsing the TIF headers is far more straightforward in inline ASM than farting around with Delphi high level code.
 
You want to use the highest level language you can to develop a project with ease. You use assembly to enhance the speed or manipulation of data that a higher level language cannot or the compiler will not. This is why assembly is more likely found in drivers, embedded devices that have limited memory or processor power or operating system kernels.
 
Thanks everyone.
kpedersen said:
A fun way to learn x86 assembly is cracking software. OllyDbg on Windows, radare2 on *nix. Both support patching. (I find IDA Pro too heavy)

Last thing I cracked was probably Builder Xcessory Pro (a nifty Motif GUI builder) for digital preservation purposes.

Cracking aside, if you are looking at greenfield development, a more rewarding and immediate environment for assembly is probably MS-DOS (i.e DOSBox). Everything is just so much more accessible and there are more books, tools and community to write fun software.
Click to expand...
Funnily enough, I have been programming in DOSBox with fasm for some time. But even with extenders, DOS programming follows an 8086 programming model. I would like to practice 32/64 bit assembly programming and make a positive contribution.

In the meantime, I have a lot to think about.
 
kpedersen said:
A fun way to learn x86 assembly is cracking software. OllyDbg on Windows, radare2 on *nix. Both support patching. (I find IDA Pro too heavy)
Click to expand...
I second that. But I like IDA. There's also Ghidra.
I didn't do cracking (though I did burn some midnight oil in z3 solver problems), I played CTFs, focused on pwns. That way I played around handful of architectures: x86, arm, mips, ppc.
From that I got to do some RL exploits and had some fun around actual devices.

That's why I seconded kpedersen's post -- I too think it's the best way to get into assembly. And it's fun. :)
 
Bootcodes for BIOS (legacy), especially the one in (P)MBR, requires assembly as of quite strict restriction in size (the order of bytes!).
In these codes, even startup codes for C (crt1.o) is tooooo huge.

MBR itself is only 512 bytes, and contains not only boot codes but also partition tables. So only 446 bytes (not megabytes, nor even kilobytes!) is allowed. And /usr/lib/crt1.o is 2272 bytes (including ELF headers, though).
 
I always encourage people to learn some Assembler, because it teaches you a lot about machines, gives you a lot of understanding, and can be useful for some certain debugging issues.
But if you're not going to program 8 or 16bit microcontrollers I wouldn't recommend to make it a primary target to become a hacker on it, at least not unless you are already very sophisticated on some other languages, especially those used for system's programming.
 
Maturin said:
I always encourage people to learn some Assembler, because it teaches you a lot about machines, gives you a lot of understanding
Click to expand...
My background being electronic engineering, I grew up on machine code and assembly. When I program in C and doing things like manipulating pointers, I actually see the address lines and data lines running between the different chips and how that works. But that same background is a hindrance when it comes to learning other languages that are more Computer Science-y. I don't have a problem with PHP and I think I do OK with Python. I get impatient learning Smalltalk and Lisp. Forget Haskell. And if Brian Kernighan can't handle Rust then I'm sure I can't.

I have a real hankering to be able to write Lisp that can hand off important parts to C but I just can't seem to stay focused on learning Lisp. Kind of like how I got distracted from the subject here.
 
drhowarddrfine said:
My background being electronic engineering, I grew up on machine code and assembly. When I program in C and doing things like manipulating pointers, I actually see the address lines and data lines running between the different chips and how that works. But that same background is a hindrance when it comes to learning other languages that are more Computer Science-y
Click to expand...
As someone with an actual Computer Science degree, I can say that higher-level languages aimed at web design and UI design are really venturing away from what I see as 'real' computer science, and into realm of providing people with eye candy. In the meantime, I see a background in machine code and assembly as the surprisingly important foundation behind squeezing more performance out of metal, and being able to manage it conveniently. Those Directed Acyclic Graphs - knowing the theory is what helps a lot when troubleshooting your way out of dependency hell. And yet, it's surprisingly easy to implement the tree data type using asm.
 
drhowarddrfine said:
Kind of like how I got distracted from the subject here.
Click to expand...
Can't relate. I never pull a topic off track. ;)

I wonder if the AI hype will bring assembly back. For vibe coding, it tends to be a write-only approach anyway because many of the people have no idea what the LLM is churning out.

So they might as well vibe code in assembly. Plus the LLM might(?) be able to put optimized snippets of assembly together by scraping patterns from existing hand-crafted examples. It also kind of solves the issue with architecture. The LLM can just churn out any as needed.

What a boring future...
 
too lazy to read the complete thread but something else to consider...

x86 assembler is most relevant in business servers and workstations. If you expect or hope to work in embedded, control, or power constrained systems then you're going to want to understand ARM assembly code. and yes, understanding assembler is still an important part of any computer engineer's bag of tricks. There is still a lot of opportunity and need to write optimized assembler in those environments. Get to know the asm("") statement/function in your favorite C compiler. For RTOS programming it is sometimes the thing that makes a busy loop work by inserting asm("nop;nop;nop;nop...") to spin for a needed amount of time.

Another assembler use I find myself doing is implementing memory based mutex with atomic assembler operations. sometimes it's just easier than bringing in a library that provides mutexes.
 
You must log in or register to reply here.
Back
Top