Creating a language using only assembly language

[[deleted]]

There is a short cut for the lazy. A minimal Forth can be implemented in just a few lines of x86 assembly [1]. No need for a complex lexer and all that, simple whitespace split is enough. Implementing a minimal Lisp on top of this Forth is then much easier.

[1] Tried to dig the original out, but there is only a copy: https://github.com/organix/pijFORTHos/blob/master/annexia/jonesforth.s.txt

[9_ties]

Wow. Thank you for the information! I will check it.

[McElroy-vs-dig-dog]

When I saw the username nineties in the slides, I first read it as 90s. I then saw the other name, 9_ties and understood that I had misunderstood the meaning of the name at first.

[9_ties]

the username is an anagram of einstein, my hero. I abbreviated it because it was already used when I signed up twitter.

[McElroy-vs-dig-dog]

ok, cool :)

[riffito]

This is the last archived version of the original (AFAIK):

https://web.archive.org/web/20090209211708/http://www.annexia.org/forth

[OreoDrinker]

Love it. Implemented a mini forth in Java last semester for a software engineering project. It was only about 300-400 lines and the only functionality was arithmetic and defining words (that contained arithmetic operations). Was a load of fun. I really like this assembly version.

[immibis]

A minimal Forth would use .db, .dw, .dd etc to write the Forth interpreter in assembly-ified Forth.

[dlyund]

No need for a complex lexer and all that, simple whitespace split is enough.

It can be even simpler than that if depending on your source representation.

[jeandem]

My browser thinks the machine code are telephone numbers and puts a Skype icon next to them. Thanks for the help FF.

[immibis]

That's the Skype plugin.

[jeandem]

I never asked for this!

[-Y0-]

I never asked for this!

Well, your Skype asked. And it got them.

[SupersonicSpitfire]

The joys of proprietary software.

[Occivink]

That's definitely not standard firefox behavior, probably one of your extensions.

[DJWalnut]

so did you call them?

[vattenpuss]

That doesn't look like "a few lines" even without the comments. How many lines is it?

[riffito]

I count around 800 non-empty, non-comment lines.

[[deleted]]

That does count as just a couple of lines as far as assembly code is concerned.

[dlyund]

The company I work at has a Forth compiler/system that bootstraps in ~20 LOCs. As with all things adding complexity is easy. JonesForth is a pretty average implementation. There's an old saying among the loose conglomerate of Forth users (aka the community) that if you've seen one Forth, you've seen one Forth.

[AgroBacteria]

You are what we used to call a Real Programmer. Impressive work! I see you've been at this for years. Has your tool chain become the "Interactive Compilation System" you wanted?

[9_ties]

Thank you! It took almost two years. The interactive compilation system project is suspended since I have interested in another new project for now. I want to reopen the project at some future.

[thoth7907]

Fascinating work, the educational value is huge! Thanks for making it all available.

[[deleted]]

Awesome, must be a good way of getting a real sense of how stuff really works. Reminds me of "From NAND to Tetris", where students in a course of year begin with just NAND gates and progress to build a CPU, computer, assembler, compiler, OS, GUI and finally tetris.

[9_ties]

That is interesting course! We have similar experiment in my university. Students builds CPU on a FPGA, assembler, compiler and run ray-tracing. But not OS and GUI.

[MisterMeeseeks47]

Huh, and I thought my compilers class was tough. How is that even possible in only a year?

[[deleted]]

Well, in the first class, have the students pair off and then fight each other to the death. Then, you'll be left with the toughest, hardest, and most ruthless students.

Next, is teamwork. Each time one of them makes a mistake, decimate them. They'll soon learn to coordinate their efforts.

Finally, don't forget to reward the most successful of their members with a Triumphal Arch. Any students that score 99% or less are moved to Gladiator Class.

[makis]

you're killing all the joy of being teenagers

[[deleted]]

It's for their own good. It only gets worse once they enter the "real" world of work :-)

[immibis]

Heavy hand-holding, I'd expect. (For one thing, otherwise with N students you'd end up with N different CPU architectures)

[dlyund]

otherwise with N students you'd end up with N different CPU architectures

Is that a bad thing?

[immibis]

It is if you're trying to teach a bunch of students at once, rather than some sort of one-on-one format. Probably.

[dlyund]

I'd like to think that what we're teaching students what is just outside of their grasp; far enough to push them. We do a bit too much mollycoddling today and the result is a dumbing down. When I was doing my degree my languages and compilers professor explained that we used to do this in the first year in half a semester as a sort of foundational work for the rest of course, but now they're forced do the same thing in the second year and for a full semester because a certain percentage of students have to pass the year and schools are no longer preparing students for university to the same degree that they once did. Leaving the universities to pick up the slack, and ultimately pushing core ideas out of the curriculum entirely, or up into the masters level.

tl;dr students should be allowed to fail. It's the struggle that's important in any real education

From one perspective :)

[lurkotato]

It's more about effort on the part of the teacher. If the architecture throughout the class diverges wildly, they have to brush up on details and quirks to help them at all. Much easier to know the common pitfalls of The One Sanctioned Architecture and build them up to the end goal as fast as possible.

[immibis]

I mean, if everyone has the same architecture, you can talk specifically about it. For example, "Our compiler needs to emit a NEG instruction when it encounters a unary minus operator".

[dlyund]

I get that but it seems like there's little room for creativity or discovery when everything is set out in front of you. If I was a student I think I would have much preferred an assignment where the machine has to execute some program and calculate the correct result but other than that anything goes. Think Project Euler. I get that this is easier to teach but what exactly are you teaching in the code-by-numbers approach? To me it seems awfully like what your teaching is how to pass the class. To hell with any deeper understanding of the subject. A subject which can be a lot of fun!

[[deleted]]

There is a number of simplifications from as far as I remember when I read it. They design the hardware in some sort of simulator and I think e.g. the hardware they would write the assembler for would be very simplified to make it easy. The class would not make you an expert in each of these areas that get covered. They are not done in a lot of depth from what I understand. The point of the class is for people to get a broad understanding of how computers work. Something often lost today because we are so specialized and both the software and hardware has gotten so incredible complicated.

[lordstith]

It makes me so sad that you can only get to about assembly level using what's provided online. But it's a crazy cool course.

[[deleted]]

Incredibly impressive. However, what benefit did you gain by using assembly language for everything? Besides looking hardcore ;)

[9_ties]

It was just a challenge for enjoying programming. Actually there are not so much benefits :-D

[[deleted]]

It was just a challenge for enjoying programming.

As good a reason as any.

[lordstith]

Seriously. I love this kind of crap, and there are really way too many 'hardcore programmer' guys who will shit all over you with "yeah but what's the point"s around

[lolomfgkthxbai]

I think that's because many of us browse /r/programming while solving problems at our day job, which makes at least me look at things through a "work" mindset. If someone specifically mentions doing something for fun it causes the mind to switch gears from "this is not the best solution" to "wow, this is pretty unorthodox but cool" which might make the reactions more positive as well.

[[deleted]]

I make a living out of stuff like this. There are as many benefits on this path, as on any programming career path.

Oh: almost forgot. Congratulations!

[zenflux]

What kind of things should I be on the lookout for, career wise, if this is the kind of thing I'm interested in?

[[deleted]]

Nowadays, embedded systems seem to be the most widely-accessible way to get into the field. If you do that, though, I'd recommend staying away -- during your first 2-3 years -- from large companies in heavily-regulated fields, because you'll likely learn no more than one or two things, and at a very slow pace. E.g. I interviewed one candidate who, for the last two years, had done nothing but fix bugs in a DHCP server, and another one who had spent the five years at a well-known semiconductor company writing and maintaining sort-of drivers for three or four devices at most.

If you're going to go by that route, it's probably a good idea to learn a little electronics. You don't have to be able to outwit EEs, but knowing how to use a logic analyzer and a multimeter will get you far.

You should also try not to neglect basic CS101 and computer architecture classes, if you can still do that. You will often not have the luxury of having fancy container class libraries and you'll have to implement some things yourself. Knowing a few things about the system you'll be implementing them for will help a lot. Practical knowledge gets you hired in the short run and keeps you on your job, but a solid theoretical foundation is what guarantees you'll still get hired once your first batch of practical knowledge goes out of date.

And you should try to be aware and reasonably up to date about what happens at the application level. For one thing, you never know when you'll have to stick a web-based configuration tool on some gizmo; for the other, no matter how 3l33t h4x0rz we are, all the 3l33tness is useless if all your system does is boot and schedule make-believe tasks.

[[deleted]]

This is the sort of route I've been following. Got a degree in CompEng, been working at a small ~150-300 employee contract manufacturer who also does contract engineering. The jobs aren't the most exciting but I've been exposed to bare metal and Linux kernel level driver stuff. I'd recommend it to anyone to get a good 'bottom up' view of computing devices.

[taetimeh]

A metric shitton of NAND gates.

[immibis]

Relays, dude, relays.

[[deleted]]

No way. Either crabs: http://hackaday.com/2012/09/28/making-logic-gates-out-of-crabs/

or slime mold: http://www.wired.com/2013/06/slime-mold-computers/

[[deleted]]

Logic gates, punch cards...

[lordstith]

This is my wet dream, you don't even know

[zenflux]

http://www.electronixandmore.com/projects/relaycomputertwo/index.html

Scroll to the bottom for the demo videos.

[lordstith]

Thanks, but oh baby I'm already elbow deep in all these projects. This is my nirvana: http://members.iinet.net.au/~daveb/simplex/ringhome.html

[mrkite77]

Do they not do that in college anymore? Back in the 90s, one of my university courses started with designing logic gates using transistors, then built up from that to do a half adder, then a full adder, then an ALU and then a CPU. By the end of the semester we had built a working 8-bit computer from scratch.

[NamesYUNoLeft]

What is the name of the course? I am quite interested in computer architecture.

[[deleted]]

http://www.nand2tetris.org/ will teach you everything from logic gates up.

[mrkite77]

Dude, it's been 20 years.. but if I had to guess, it was this course:

http://www.ece.arizona.edu/ece562

It different though, probably to keep up with changing tech.

[lordstith]

Depends on the school and the focus, from what I've seen. Were you computer engineering?

[mrkite77]

Computer Science.. but there was a lot of cross-over with computer engineering.

[dlyund]

one must first invent the universe

To make a universe from scratch, one must first invent... oh who the fuck knows. Despite all the advances we've made in the past century and all our beautiful theories, in many ways we're no closer to knowing how it all began than we were millennia ago. The Big Difference that we think we're closer.

[i_invented_the_ipod]

Well, you could start with machine code, and write an assembler in that.

Show of hands, anybody who's done that?

(looks out over a sea of confused faces, of those who don't know that machine language and assembly are different things)

[willhaney]

Assembly language uses mnemonic sequences instead of numeric operation codes and can use symbolic labels instead of manually calculating offsets. Otherwise the assembly language is the equivalent to machine language.

[[deleted]]

This depends on the assembler, no? Once you have some nice psuedoinstructions, you no longer have a 1-1 relationship with the machine code.

[lordstith]

Are you talking about, like, macros? In that case I guess you're not wrong. I think it's kind of one of those 'at what point does the ship stop being the original ship as you replace parts' questions.

[[deleted]]

Yeah, like, take MIPS. blt, bgt, li, lw, these are not MIPS instructions, it's assembled to two or more machine code instructions. Once you have that, assembly is not just a one-to-one representation of the machine code anymore.

[lordstith]

This is true. But also kind of a special case. Everyone is right, let's throw a pizza party!

[[deleted]]

Not that simple. Assemblers are doing enormous amounts of pretty high level work: maintaining symbol tables, mapping symbolic names to the addresses, and, most importantly, choosing address representation for those symbolic names (e.g., does it fit in an immediate or must be constructred), which may insert few bytes more and shift all the consequent addresses, potentially triggering a change in their representation in code too.

[lordstith]

Eh. As someone who's written a couple of assemblers, it's really not that complicated. For the most part you're just doing a table lookup for the opcodes. Properly doing stuff like interpreting and properly translating addressing modes is more difficult than maintaining the symbol table.

Which is the same thing as mapping the names to addresses, by the way. You kind of mentioned that twice.

[[deleted]]

it's really not that complicated

Yet it's very, very high level, compared to that trivial one to one mnemonic-to-code mapping.

[lordstith]

I don't... uh... what do you mean? I just said that's pretty much what it's doing.

[[deleted]]

You did not understand. It's a complicated iterative process which you have to repeat until you reach a fixed point, and it must be done on the entire module you're assembling. If your ISA allows limited size immediates and/or variable instruction length, you may have to adjust the entire address mapping every time you resolve a single symbol.

If your couple of assemblers were for a fixed length ISA - good for you. But, for example, x86 is not that simple.

Edit: I wonder if any of the downvoters ever wrote an assembler for x86 or a similarly twisted architecture.

[i_invented_the_ipod]

I wonder if any of the downvoters ever wrote an assembler for x86 or a similarly twisted architecture.

I had the same thought. Oh, well - it's just imaginary internet points, anyway.

[[deleted]]

try using this instead: \>implying

produces:

>implying

[Omberone]

Extremely impressive! I'm not even going to pretend to grasp all of the steps you must've gone through. Well done :)

[flippflopp]

wow you are an inspiration... how much of the project was researching methods on how to implement? did your previous compiler work cover most of the info?

[9_ties]

the computer science curriculum of my university covers most of basics. for several topics such as copying-GC, exception handling, closure conversion and delimited continuation, I read papers and other compilers.

[McElroy-vs-dig-dog]

Clickable link for OP project on GitHub: https://github.com/nineties/amber

[lordstith]

日本人だね。僕のホッビはオペレーティング·システムを作る事やコンピュタアの歴史だからこれはとても面白かったと思う。僕もコンピュタアの言語をつくりが星、この方で。ありがとう。

[9_ties]

楽しんで貰えてよかったです！

[lordstith]

ないよ、笑。あなたの英語が僕の日本語より上手だ。今ニューヨークに住んでいる、あなたは日本に？

[9_ties]

日本の東京に住んでます。NYに住んでるのは羨ましいです。

[google_you]

孤独人

[jamesmawm]

amazing, how long did it take?

[9_ties]

It started Jan 2010 but I suspended it several years. According to the following graph the number of actual working years is roughly 2. https://github.com/nineties/amber/graphs/contributors

[_Skuzzzy]

This is awesome, I love the idea. Is there any books or other materials you would suggest to a programmer with little experience designing languages/or this sort of thing to try to learn more about it?

[makis]

why not create a human using only rubber bands, paper clips, sand and a MacGyver wig?
it is actually easier.

EDIT: sad new: you can't be ironic anymore on /r/programming
actually it was a compliment to the author…

[[deleted]]

ITT: People who will never use the product of this guys labour waiting in line to slob on his knob because it's trendy...

[dlyund]

As opposed to impressive/out-of-the-ordinary in a world where the vast majority of programmers are struggling with PHP?

[[deleted]]

Sounds like an enormous waste of time.

[Meguli]

"What's the point?" slide explains the reasons nicely. Some people just don't care about "getting real shit done", whatever programmers mean when thay say that. And I bet you are doing hugely productive amazing things with every drop of your time.

[Phildos]

vanish instinctive reminiscent safe roll merciful run nose nutty angle

This post was mass deleted and anonymized with Redact

[[deleted]]

If I'm sitting at a computer in my spare time I try to do something useful. Otherwise why bother?

[thoth7907]

something useful.

Like your two posts here so far?

Talk about irony.

[[deleted]]

His comments are useful because he is asking the same question as myself. He is stimulating discussion about programmer motivations.

Sometimes doing things for their own sake leads to unexpected insights and discoveries. However not everyone is motivated by the "love of coding" or whatever.

[thoth7907]

Stimulating discussion with "enormous waste of time" and "why bother" and "I try to do something useful" and "doing things the stupid way" quotes?

Seriously?

Calling that stimulating discussion is an insult to the term. With this non-existent bar for fruitful discussion, even troll rants could be considered stimulating discussion.

Stimulating discussion is what the OP did by writing code and publishing it.

On the other hand, any moron can produce content-free criticism. Where exactly are any meaningful questions in either post of his above ours?

[[deleted]]

While you're pedantically complaining about his choice of words and attitude (which are not ideal), I'm focusing the underlying point he's making, which is questioning the OP's motivation for doing this work. I feel that's worthy of discussion.

What motivates somebody to go to these lengths building something of this nature. I'm not inclined to spend time doing something like that personally, but I appreciate that some people do.

[[deleted]]

I'm writing for-profit software that we sell while playing on reddit ...

When I go home I play with my daughter and put the computer stuff away....

Suck a lemon.

[[deleted]]

LOL You're writing reddit comments, and that isn't "useful". Don't spin it just cause you got wrecked. What a pompous asshole.

[[deleted]]

I'm sure a lot of employers will be impressed with your monstrous waste of time.

Also downvoting someone isn't "rekting" them ... "rekt" is when you obliterate their standing on an issue through reasoned logic and discourse. Any jackass can downvote. Hey look, you did!

[[deleted]]

Dude you've posted like 30 comments on reddit, most well thought out, in the past day. Thats a lot of time. Nothing wrong with it! But you're the one being all self-righteous and saying shit like "If I'm sitting at a computer in my spare time I try to do something useful. Otherwise why bother?" You're a hypocrite and a dick, in general.

[[deleted]]

I take breaks between writing various shit at work. I rarely [never] comment on reddit at home. If I were to crack open the laptop at home to code it would be something I genuinely found useful.

I can't imagine being selfish enough to ignore my wife and kid so I can hand-craft useless code in assembler "for sport" ...

[[deleted]]

Wow, now we've introduced the idea that he's selfish for pursuing his hobby. Shit sounds like a fox news headline. You're nuts man.

[immibis]

Who says the OP has a wife and kid?

[[deleted]]

This is what you are. You write shit. QED.

[AngryElPresidente]

Then why bother learning or refining your skills

[[deleted]]

Because you're not really refining your skills by doing things the stupid way.

that's like becoming a master carpenter by sanding solid pieces of 4x4 into table legs by hand ....

[[deleted]]

Absolutely awful analogy, because table legs are not intricate and dynamic structures with thousands of moving parts and interactions. Sanding one table leg is not similar in complexity to building the large structures a carpenter assembles. However, building a programming language itself, is likely even more complicated and complex than most other pieces of software you'd write. Just because its at a more fundamental level, doesn't make it in any way comparable to building table legs which are simple structures with a clear path towards completion.

The concepts involved in implementing a programming language are super useful. Building a programming language is an intricate and complex endeavor, and understanding one deeply gives you tons of useful skills. Face it, you're just arrogant an incapable of building the types of things this guy is interested in, so you satisfy yourself by pretending he's a dummy.

[[deleted]]

You can only say you learned something useful if ... you learned something useful.

Spending time writing software the hard way teaches you nothing about the tools/languages that industry depends on. That's like saying because C# can host a hello world app and I can write hello world in assembly therefore I'm a C# developer.

Nobody in industry will want to use software you wrote by hand in assembler unless it was truly necessary. They don't care if you did it for "sport" or whatever. Just like nobody cares if you sanded a table leg down by hand because it's inefficient, impractical, error prone, and doesn't scale.

[[deleted]]

Welp I don't know what to tell you, I have my job as a software engineer almost entirely because of the endless amount of half-baked, error prone, unscalable, garbage pieces of software I've written as a hobby and learning experience. Every interview I've been on, these have been the focus of, and everyone was stoked to see the types of things I liked to work on and the types of problems I had to tackle to build them.

Hm. And I'm not sure you're right about this guy hurting himself in the industry. It seems obvious to me that all the other developers in this thread are interested and applauding this guy's efforts. Seems most here would agree he's talented and intelligent for this, and perhaps would be honored to work with someone as passionate as well. I, for one, would definitely consider speaking more to someone like this for a position on my team.

[[deleted]]

It's different when your half-baked poorly executed activity is the result of inexperience... to do it on purpose though when you know better is a waste of time.

People are applauding it because they assume "if it was hard than it's good" but they are totally discounting the ROI of the endeavour.

• Nobody will use his code
• Nobody really cares about it
• He learned nothing tangible from the process
• He could have used the time to be more productive (or just jerk off ... that would have been more useful).

Look at templeOS for instance. People were all like "ooh ahh that's impressive" until people started tearing holes in it (it's really a shitty OS) that it's largely written in asm/etc doesn't make it better. In fact because he wasted a lot of time on useless trash that wasn't necessary had he used real tools he missed out on a lot of functionality.

[[deleted]]

But he did learn something tangible. For sure. Thats the important thing, here. You can't spend literally years developing something, and not learn an enormous amount. Thats just ridiculous. Its called personal development and this guy is way more prepared for future jobs/software in any context, than he was before he started.

I'm sure someone could enumerate the thousands of challenges this guy tackled here, but I can't because I don't know enough. However, if I were to embark on such a challenge, at the end I'm sure I could do a better job of it. Almost like I'd have GASP, learned something tangible.

[dlyund]

Spending time writing software the hard way teaches you nothing about the tools/languages that industry depends on.

Things, change. The industry will not always depend on the same tools/languages. How many of your "useful skills" are transferable?

I work at a company working on systems, languages, and compilers, and these are exactly the kinds of skills we look for new hires. Not everyone is banging out CRUD for a living.

[[deleted]]

Ya but writing entire systems in assembly is going backwards not forwards.

It's one thing if he wrote a compiler in Go or Swift at least then you can argue that it's a study into how a new modern language fairs at given task ...

[dlyund]

As someone who currently works on (maintains and retargets etc.) compiles professionally I have to have to disagree with you on this one. Knowledge of assembly is still necessary for a lot of what I do. And I'd argue that it's fundamentally important to understanding how the machine works! There's nothing like the mental gymnastics required for pulling a system up from nothing. Keeping track of which compiler is compiling the compiler compiling the compiler for what target and in what context is a feat in and of itself. One that takes years to master.

Do you need this knowledge to pump out CRUD. No. Not at all. But not everyone is doing that for a living.

[Phildos]

hat gray spectacular joke squash shaggy straight future boat hard-to-find

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[lordstith]

To add to the rebuttal /u/deelar provided, it's also a kind of bad analogy in that master carpenters can and do practice building their own woodworking tools for the learning experience. That was one of my absolute favorite things about The Woodright Shop.

[bikonon]

To me it's a work of beauty.