> Abstractions. They don’t exist in assembler. Memory is read from registers and the stack and written to registers and the stack.
[...] But my application-coded debugging brain kept looking at abstractions like they would provide all the answers. I rationally knew that the abstractions wouldn’t help, but my instincts hadn’t gotten the message.
That feels like the wrong takeaway for me. Assembly still runs on abstractions: You're ignoring the CPU microcode, the physical interaction with memory modules, etc. If the CPU communicates with other devices, this has more similarities with network calls and calling the "high level APIs" of those devices. For user space assembly, the entire kernel is abstracted away and system calls are essentially "stdlib functions".
So I think it has a different execution model, something like "everything is addressable byte strings and operates on addressable byte strings". But you can get that execution model occasionally in high-level languages as well, e.g. in file handling or networking code. (Or in entire languages built around it like brainfuck)
So I think assembly is just located a few levels lower in the abstraction pile, but it's still abstractions all the way down...
Asm is simple enough that "mental execution" is far easier, if more tedious, than in HLLs, especially those with lots of hidden side-effects. The concept of a function doesn't really exist (and this is even more true when working with RISCs that don't have implicit stack management instructions), and although there are instructions that make it more convenient to do HLL-style call and return, it's just as easy to write a "function" that returns to its caller's caller (or further), switches to a different task or thread, etc. If you're going to learn Asm, then IMHO you should try to exploit this freedom in control flow and leverage the rest of the machine's ability, since merely being a human compiler is not particularly enlightening nor useful.
I agree entirely, great insight! I'd like to add that assembly is best enjoyed in a suitable environment for it, where "APIs" are just memory writes and interrupts. Game programming for the C64 is way more fun than dealing with linux syscalls, for example. A lower level interface enables all the fun assembler tricks, and limited resources require you to be clever.
> Asm is simple enough that "mental execution" is far easier, if more tedious, than in HLLs
Ya totally I can also keep 32 registers, a memory file, and stack pointer all in my head at once ...fellow human... (In 2026 I might actually be an LLM in which I really can keep all that context in my "head"!)
Not sure what to take away from this. __abstract works because GCC allows it as an alias to __abstract__, not because parsing the syntax is forgiving.
Abstractions do exist (disagreeing with the single other post in here) and they also exist in most flavours of assembly, because assembly itself is still an abstraction for machine code. A very thin one, sure, but assemblers will generally provide a fair amount of syntactic sugar on top, if you want to make use of it.
Protip: your functions should be padded with instructions that'll trap if you miss a return.
Neat. The author is about to stumble onto a secret.
> In Sum#
> Abstractions. They don’t exist in assembler. Memory is read from registers and the stack and written to registers and the stack.
Abstractions do not exist periodi. They are patterns, but these patterns aren’t isolated from each other. This is how a hacker is born, through this deconstruction.
It’s just like the fact that electrons and protons don’t really exist. but the patterns in energy gradients are consistent enough to give them names and model their relationship. There are still points where these models fail (QM and GR at plank scale, or just the classical-quantum boundaries). It’s gradients all the way down, and even that is an abstraction layer.
Equipped with this understanding you can make an exploit like Rowhammer.
Abstractions pretty much exist and in assembler they matter even more because the code is so terse.
Now, there are abstractions (which exist in your brain, whatever the language) and tools to represent abstractions (in ASM you've got macros and JSR/RET; both pretty leaky).
> Abstractions. They don’t exist in assembler. Memory is read from registers and the stack and written to registers and the stack.
[...] But my application-coded debugging brain kept looking at abstractions like they would provide all the answers. I rationally knew that the abstractions wouldn’t help, but my instincts hadn’t gotten the message.
That feels like the wrong takeaway for me. Assembly still runs on abstractions: You're ignoring the CPU microcode, the physical interaction with memory modules, etc. If the CPU communicates with other devices, this has more similarities with network calls and calling the "high level APIs" of those devices. For user space assembly, the entire kernel is abstracted away and system calls are essentially "stdlib functions".
So I think it has a different execution model, something like "everything is addressable byte strings and operates on addressable byte strings". But you can get that execution model occasionally in high-level languages as well, e.g. in file handling or networking code. (Or in entire languages built around it like brainfuck)
So I think assembly is just located a few levels lower in the abstraction pile, but it's still abstractions all the way down...
Asm is simple enough that "mental execution" is far easier, if more tedious, than in HLLs, especially those with lots of hidden side-effects. The concept of a function doesn't really exist (and this is even more true when working with RISCs that don't have implicit stack management instructions), and although there are instructions that make it more convenient to do HLL-style call and return, it's just as easy to write a "function" that returns to its caller's caller (or further), switches to a different task or thread, etc. If you're going to learn Asm, then IMHO you should try to exploit this freedom in control flow and leverage the rest of the machine's ability, since merely being a human compiler is not particularly enlightening nor useful.
I agree entirely, great insight! I'd like to add that assembly is best enjoyed in a suitable environment for it, where "APIs" are just memory writes and interrupts. Game programming for the C64 is way more fun than dealing with linux syscalls, for example. A lower level interface enables all the fun assembler tricks, and limited resources require you to be clever.
Then you goto hell…
> Asm is simple enough that "mental execution" is far easier, if more tedious, than in HLLs
Ya totally I can also keep 32 registers, a memory file, and stack pointer all in my head at once ...fellow human... (In 2026 I might actually be an LLM in which I really can keep all that context in my "head"!)
there's an interesting new API skill for the human cortex v1.0, that allows for a much larger context window, it's called pen and paper.
8 registers are sufficient; if you forget what one holds, looking up at the previous write to it is enough.
Contrast this with trying to figure out all the nested implicit actions that a single line of some HLL like C++ will do.
Not sure what to take away from this. __abstract works because GCC allows it as an alias to __abstract__, not because parsing the syntax is forgiving.
Abstractions do exist (disagreeing with the single other post in here) and they also exist in most flavours of assembly, because assembly itself is still an abstraction for machine code. A very thin one, sure, but assemblers will generally provide a fair amount of syntactic sugar on top, if you want to make use of it.
Protip: your functions should be padded with instructions that'll trap if you miss a return.
Neat. The author is about to stumble onto a secret.
> In Sum# > Abstractions. They don’t exist in assembler. Memory is read from registers and the stack and written to registers and the stack.
Abstractions do not exist periodi. They are patterns, but these patterns aren’t isolated from each other. This is how a hacker is born, through this deconstruction.
It’s just like the fact that electrons and protons don’t really exist. but the patterns in energy gradients are consistent enough to give them names and model their relationship. There are still points where these models fail (QM and GR at plank scale, or just the classical-quantum boundaries). It’s gradients all the way down, and even that is an abstraction layer.
Equipped with this understanding you can make an exploit like Rowhammer.
https://en.wikipedia.org/wiki/Row_hammer
Abstractions pretty much exist and in assembler they matter even more because the code is so terse.
Now, there are abstractions (which exist in your brain, whatever the language) and tools to represent abstractions (in ASM you've got macros and JSR/RET; both pretty leaky).