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It’s an interesting strategy, but I question how much it pays off, if at all. Very few parts of a program benefit from manually tuned assembly compared to the naive C implementation. Writing everything in assembly adds an extra layer of thought, which even for an LLM is additional effort that could have been used for targeted optimizations instead. It makes it harder to notice patterns that have been trained into the data set, from security problems to performance opportunities.

On a long enough time frame with enough tokens invested there’s probably not a difference, but being written in assembly by an LLM doesn’t imply optimal to me. I’d almost prefer having an LLM rely on higher level abstractions offered by a programming language rather than rolling everything itself. After reviewing a lot of LLM code, even at Fable and Sol levels, I just don’t trust that LLMs are writing optimal code. Assembly makes it harder to even review.

I do it find it very fun and entertaining. This is a component and I’m grateful that it was shared.

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It will make the code slower.

Writing maintainable assembly is at odds with writing fast assembly in most circumstances.

A key optimization that's hard to pull off is inlining.

An optimizing compiler can see that a method is small enough that it can be pulled into the caller, it can then further eliminate from that smaller method branches that can't be executed due to the nature of the caller (Imagine calling a function with a `bool` parameter and you send in `true` at the call site).

To make the code faster in hand written assembly, you have to do the inlining, but that makes writing more structured code a lot harder. You are duplicating logic paths in the name of performance.

Not to mention the fact that the compiler gets updated and knows about more instructions and architectures then you do or then you could have. Hard to write the FMA instruction if it didn't exist when you were writing the assembly in the first place.

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Claude has surprisingly good knowledge of X11 protocol.

The other day, colleague showed me a (pretty basic) terminal emulator written in one-shot by Opus. Kicker is - that was compiled to a 30 KB static binary. That's right. No libX11, no libXfont, not even libc.

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Yeah, I've had it work on an X11 server using a Ruby X11 protocol implementation instead of libX11, and it just rushed ahead and added support for a bunch of missing requests and responses. None of that is hard - it's all very well documented - but it's tedious.

My terminal emulator using the same binding also started out hand-written but Claude overhauled that too recently and it knows vtxx escape codes far better than me too.

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Only because the X Window System is very heavily documented, e.g., in the excellent "The Definitive Guides to the X Window System Series".
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No libc? It used inline assembly routines?
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Yes, something like this:

  static inline long read(int fd, void *buf, long count) {
    register long rax asm("rax") = __NR_read;
    register long rdi asm("rdi") = (long)fd;
    register long rsi asm("rsi") = (long)buf;
    register long rdx asm("rdx") = count;

    asm volatile(
        "syscall"
        : "+r"(rax)
        : "r"(rdi), "r"(rsi), "r"(rdx)
        : "rcx", "r11", "memory"
    );
    return rax;
  }
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The linux kernel also has its own headers (IIRC it was something like <asm/unistd.h> and/or <sys/syscall.h>, but might depend on architecture and version) where it will provide the stub asm statements.

In my memory the syscall ABI has changed a few times (i386 had int $0x80, then sysenter, then abstracting it in the vdso, then amd64 has 'syscall'), so it may be easier to let the kernel header provide the mechanism.

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The Linux syscall ABI is (famously) stable; on x86* you can still call into 0x80 just fine. There might be new interfaces made available, but existing programs shouldn't break. Although, in C there could be value in abstracting over the per-platform differences like int/syscall. I've only ever done raw syscalls from assembly where portability was rather moot:)
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It's quite easy to get it to do syscalls directly, I even got Fable to do a simple standalone TLS implementation (in C). Not really useful since it hardcoded a set of supported algorithms etc., but it's fun to see how "simple" you can force it to go.
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assembler is fun and kinda easy. easier than learning any JS framework in my opinion serious here.

Modern macro assemblera are fun

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Sounds like another prompt is in order to re-write the code
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Once you create an abstraction (like a macro, routine, language) you forfeit the benefits using machine code gives you wherever you use that abstraction, since there could be some bespoke implementation that solves the problem.

That entire point is moot here because the abstraction in this case is a massive ball of crap and it's used everywhere. So you never get the benefit you think you would for using a lower level language. That's why generally LLMs are best with python and even better with a "harness" (domain specific framework and language)

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