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Is Assembly Programming Still Relevant, Today?
intelinsight asks: "Consider the following question given the current software development needs, and also the claims of the Assembly lovers for it being a language that gives one insights of the internal working of a computer. How relevant or useful is it to learn Assembly programming language in the current era? "
It's good to know how things work underneath the hood.
Isn't knowledge of assembly language for microprocessors required to create a higher level programming language?
Previewing comments are for sissies!
Please remain ignorant of all lowlevel details of your deployment and development platforms.
Please continue to treat both computers and the tools you use to program as magic black boxes.
That way old dogs like me will still have a job.
How we know is more important than what we know.
For good programmers, yes.
You really only need to know how to program assembly if you want to be a good programmer. If you want to be a crappy one, learn Java or C#, pretend pointers are magical, and be happy with your life. (I'm not saying those are bad languages, I'm just saying they're opposite from assembly)
Also, a lot of embedded work is still done in assembly because with a lot of low-level industrial work having very precise clock-counts on everything is very important.
-Bill
Well, given that the world runs on embedded systems, and will probably become more reliant on even greater numbers of even more complex embedded systems, I'd say assembler will be around for quite a while. However, in terms of game programming or something, it's probably not amazingly useful any more. It is my understanding that most of the API calls to advanced graphics libraries are about as optimized as they are going to get. Clearly you don't need it to write a medical billing application.
I would not encourage universities to start pumping out CS graduates who have never seen assembly laguage, and don't expect it to phased out of the average Electrical Engineering curriculum any time soon.
Frankly, I don't think it's a very good question. It's sort of like saying, "Given that we now have calculators and computer algebra systems that will do the math for us, is it really worth it to waste students' time learning the nuts and bolts of mathematics?" It has been my (limited) experience in software engineering that knowing how something works on a deeper level will almost always be an asset, and at the worst have no effect at all.
Do you write drivers? Or do you need highly optimized algorithms? What about really low level firmware stuff?
In other words, yes, there are good reasons for knowing assembly. Whether or not you'll actually use it is another matter entirely. Just depends on what you're working on.
Actually I wouldn't be surprised if in about 10-15 years assembly programmers are in higher demand since none of the CS schools these days ever teach assembly anymore.
How do compilers know what to compile to? Magic? Imagine if all the assembly programmers died: who'd maintain & update compilers, embedded devices, many realtime instruments, etc. ?
Trolling is a art,
That's a pretty fine line there. If you can understand asm well enough to debug such issues, I would argue that you also probably know enough to write it, or at least very nearly so.
I would say that you need to know how to program in assembly language, though it doesn't really matter much which ISA you use---MIPS, x86, PPC, ARM, whatever. What matters is the ability to understand what's really happening at a low level so that you don't do stupid things in high level code that cause your machine to have a seizure.
For example, once you understand that your CPU only has a limited number of registers, you'll understand why (on some CPU architectures) it is a good idea to limit the number of function arguments so that they can be passed via registers, and that you should put the arguments that you are most likely to use at the beginning of your prototype so that they have the best chance of already being in a register.
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Knowing assembly language is like knowing how to an internal combustion engine works.
.NET, or web-based programming, knowing assembly language won't help much.
For most drivers, it's a curiosity.
For most auto mechanics, it's somewhat useful.
For anyone doing engine repair, it's very important.
If you are programming at a hight level like Java,
It's only when you are using a language like C where knowing how the chip works can actually help you write your code does it really matter.
Anyone doing systems programming, real-time programming, or anyone who needs fine control over their program's execution should learn assembly.
For non-programmers and very high level programmers, it's about as useful as studying Shakespeare or business law. It'll make you a more well-rounded person but it won't help your code run faster.
Knowledge is how to play a game, intelligence is how to win, wisdom is knowing what game to play.
Like Duke knows anything of electrical engineering. It only takes a State student to tell you that (or a Carolina student, but they can go to hell).
Curriculum here started with learning about what a gate was, how it was made from transistors (which were magic black boxes then), from gates we learned adders and other MSI devices, and eventually got to an abstraction of a microcomputer. Assembly then was a Godsend and now using that same assembly language, we've implemented C.
Point is, reference a school for electrical engineering, make a better choice than masking Duke to the country. I mean, look here at State, Ga Tech, Va Tech, MIT, Stanford, Princeton, USC, etc.
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Frankly I think a good programmer is somebody who writes well documented and designed code. I don't think somebody's knowledge of the low level assembly programming necessarily helps with that. I'd rather somebody wrote somewhat inefficient code that I could read and, as needed, optimize, then have some spaghetti pile that nobody could understand but was lightning fast.
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Seriously, assembly is important for all the reasons you noted, but also for some others. If you know assembly, the chances are:
All software engineering, computer science and programming courses should start by requiring people to program a non-trivial application on an ARM processor, or something with an equally limited instruction set, in pure assembly. Why? Because then you get people who think, who program with care and forethought, who think of bloat not in terms of adding more RAM, but in terms of opportunities for bugs, glitches and gremlins. Sure, you'll get more dropouts. The computing world doesn't need more code monkeys, so it's no loss if they did. Who needs a society of half-baked, semi-literate coders?
This is not elitism, because I'm not saying that anyone should be excluded from the profession. I don't think they should. What I do think is that society needs to make damn sure that the typical coder isn't the worst coder, which is what you get if people are trained to NOT think but to let the computer do the thinking for them. Windows may act like a HAL-9000 at times, but trust me, it isn't remotely capable of anything resembling thought. A bad design or a poor implementation will not be rectified by some magical intelligence in the machine, because there isn't any.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
Hmm. Assembly is still relevant and useful for certain tasks, of course.
/David
But two things come to mind:
1: Handcoders can code better than good compilers?
Yeah, in some cases after a lot of refining. But it is not as easy as it once was.
Compilers have gotten much better and processors have gotten a lot more complex. It's not just "how many clock cycles does this instruction use?", you also have to take various forms of micro-parallelism (pipelining, branch prediction, etc.) and cache hierachy issues into account.
2: It's good to know what goes on under the hood, sure.
But in many, many software developer tasks, early optimization is the root of all evil.
I would actually much rather recommend a top-down approach for most problems, abstracting away low-level details, rather than going bottom-up. The teaching approach of the great "Accelerated C++" comes to mind.
A lot of developers that know a little or a lot about low-level programming write less than excellent code in other regards (algorithmic complexity, design, re-use, etc.) and they can't seem to stop focusing on performance throughout the process.
For most problems, performance isn't critical, and even when it is, it might be better to look for algorithmic enhancements (lowering complexity) rather than do low-level fiddling.
I see it this way: assembly is still used today, but only in a smaller niche. But that's not the only reason it's relevant. I think it's a good knowledge to have, even if you'll never use in practice, but it's concepts help you understand the whole. Much like Math, or basic Physics.
factor 966971: 966971
I think some assembly knowledge is important, at least to understand pointers.
But, shaders are hardly written in assembly anymore, for all the good reasons.
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Communicating in Morse code. It's a pain in the ass to learn, but when you do, you find the rewards more than justify the effort spent.
:-)
Also, it's good to remember that Assembly language is just one more tool in a programmer's tool box. I wouldn't write throw-away scripts in Assembly language, just like I wouldn't use C. I'd probably use Perl, Python or shell script, as necessary. When you need to hand-tune that algorithm to get that last little boost in performance, being able to drop down to Assembly language can save the day. Too bad it is a dying art.
On another note, I agree with the other posters that said learning Assembly language allows you to learn the hardware better. 8086 Assembly language was my second language (after BASIC), and I used it for several years, until I started using Windows and found it was much easier to write a Windows program in C
No matter where you go... there you are.
They stare at the code for a while, make wild guesses about how the problem could have happened, add a lot of couts, and hope for the best. Seriously.
I think you're suggesting that for certain kinds of optimization it's as important to know about machine architecture and organization, I.e. things like cache associativity and size, relative speed of memory vs. registers vs. cache, etc., as it is to know or optimize the use of particular "assembler" (actually machine) language instructions. Good point. Still, if you want to know how many memory accesses either the presupplied strcat or your own alternative are going to issue, and which addresses they're going to hit, knowing machine language is a big help.
Answer to "What's hard about pointers?"...
There are people who cannot grasp the difference between "a thing" and "a respresentation of a thing". In fact, there was an entire century where almost the entire school of French philosophers were unable to grasp that there was a difference.
For pointers, it comes down to realizing that a pointer to memory is not the memory, it's a representation, and the real memory lives somewhere else: at the dereference of the pointer. And at that location it takes up real space. And so does the representation (but it's comparatively tiny).
The ability to make this disctinction comes naturally when you've written assembly code of any complexity, since you've had to manage the memory yourself. But if you've never done that, or, worse, you've only ever programmed in languages which eschew pointers and try to pretend that their own internal implementations don't use them, even if they won't let you use them, well, then, you've got a conceptual problem. An that conceptual problem is going to be very hard for you to overcome.
It also makes it very, very hard for someone to understand row-major vs. column major languages, or how you would link a program in one against a library in another, and be able to usefully communicate your data between the two. Or it makes it hard to understand the difference between "call by value" and "call by reference.
If I'm interviewing someone, and it becomes clear that they need a "code interview" because some things don't add up between their banter and their resume, the first thing I whip out is a pointer problem.
-- Terry
You're writing software for any chip, on any platform, that requires direct hardware level access, e.g. device drivers, boot code, or core-features. No machine, no matter how fast can be programmed exclusively in C. For example, in C you simply cannot a DCR on a PowerPC. You need a special instruction w/o a high-level language equivalent.
You're certainly right, but programming language extensions could get around these limitations. For instance, I think the PIC C compiler, which is not really standard C, has an extension that lets you write and install an interrupt service routine without any assembly. One could imagine such extensions for almost any hardware feature; it's just that compiler-writers rarely bother to offer such extensions.
Maybe, except that not many assembly programmers can make faster code than a C compiler anyway. It's no use being a mediocre assembly programmer.
As a marketable skill, assembly won't get you anywhere. There are a handful of places were knowing a specific assembly language is a prerequisite (boot loaders, deeply embedded applications, etc.) but these are just a fraction of the overall job-space for software engineers. Most software engineers never mess with assembly; they are, in fact, afraid of it and think that it's evil.
Given all of that, assembly language *is* the hardware/software boundary. It's where all of the fancy abstractions from CS dissertations meet reality. Understanding computer architecture is a huge asset as a software engineer, and to properly understand how software and hardware interact, you have to learn at least one assembly language. There is no alternative. For most people, it is an unpleasant experience, but the payoff is enormous. The learning process that you undergo while learning assembly will change the way that you see your software and will help you understand why your code is so slow and how to make it fast by design.
I have one last point. When you tell a potential employer about the low-level stuff that you know or work that you've done, your assembly skills are a proxy for understanding how hardware works (at least to interviewers with half a brain). If their software needs to run fast, they'll be happy that you understand the deep magic of hardware.
(Incidentally, I think that the fraction of software jobs that require an understanding of hardware and knowledge of assembly languages, linker internals, etc., are the only fun ones and the only ones worth having. So I learned MIPS, ARM, PowerPC, and TMS320C6 assembly, and they have all served me very well because I don't have to refactor C# for a living.)
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> Seriously
Yeah, right, let me go and find myself an IBM/360 to get exposed to... "Seriously" - you are suggesting to ignore, what, 90% of computers in the world - hell, the one sitting on your desk.
How can this be serious (or insightful).
This is particularly true for programs that
Knowledge is how to play a game, intelligence is how to win, wisdom is knowing what game to play.
100% agree. There are a lot of missing features in C which require assembly nowadays :
:-(
- bit rotations => have to be coded by ORing bit shifts and masks
- bit counting (FFS/FLS) => have to be cleverly coded to avoid iterations
- locking => you need the lock instructions/prefixes of CPUs
- prefetching => idem
- memory barriers => idem
And the list is long. What do we do instead ? typically, bit operations are done by hand with 100 times slower operations and using jumps and loops while a single instruction almost always exists. Locking accesses is performed through calling functions from heavy and slow libraries such as pthreads.
It always strikes me to see code doing such a thing :
pthread_mutex_lock(&counter_lock);
counter++;
pthread_mutex_unlock(&counter_lock);
While in assembly you would be able to do this on many platforms :
LOCK INC counter
Which is basically what is done in the mutex_lock (with added tests).
We really need some C extensions to access the lower level, but unfortunately,
the trend is the other way
Willy
Sorry, but that "multiplatform code" you speak of requires a lot of Assembly code under the covers. For the most part assembly is delegated to hardware integration, drivers, and performance tweaks. It is still vital to the industry... I will say that most developers have no need to learn it, but it is far from obsolete. C is still widely used for lower-level libraries and APIs, I wouldn't suggest it as a career path for most developers, but it's still pretty necessary.
Personally, I like higher-level languages that abstract a lot of the inner workings such as C#/.Net, Python or Java. I like to concentrate on solving problems or making things work. However without those that *DO* write in assembly, nothing I write would *RUN* anywhere.
Michael J. Ryan - tracker1.info
To consistently beat a C compiler: Write your code in C with inline assembly if required, then compile through Assembler to get assembler source code. Next, hand tweak the assembler code and add C as comments. Pretty soon you will start to think like a compiler and your C code will get better too!
I've worked with people with very focused high-level programming skills and found that while they could write mostly decent code, their code was also most likely to fail in production since they were completely mentally removed from concepts like disk-seek times or bandwidth constraints.
/., not many would want to admit to being a Group 2er but I have no problem with it. For example, Group 2ers would also know when a Group 1er's code sucked, from a performance standpoint. Coders with a trailblazer mindset are rarely good optimizers.
I'm not a great programmer, but I've always had a good "sense" (for lack of a better word) about technical things. I worked a bit at a company doing mid to high level (V)FoxPro programming. They put me on the least desired machine and I set to work. Within minutes I realized the machine was not running right, CPU at 100% or close to it most of the time. Turns out it was virus-infected (despite NAV, of course). I found the name of the EXE, renamed it in autoexec.bat before it loaded, then deleted same. Problem solved and the oldest 'clunker' became a quite acceptable computer.
I think this story illustrates the two broad classes of programmers. (1) those able to get a task done, no matter how nerdy or obscure (but who are pathologically incapable of documenting their work, or teaching others) [e.g. my co-worker who had used that computer for months or years without noticing the virus] and (2) those who are good at interface, optimization, and documentation but lack the penetrating power to solve the more difficult problems [e.g. myself -- I had to leave that job because I couldn't 'crack' the OO stuff].
Speaking to this thread's main question: both classes of programmer would need to understand some assembly, but for different reasons. Group 1ers would likely end up using it (or having to debug/change it) from time to time -- and it would be no big deal to them to learn it, use it, whatever. Group 2ers would likely want to know _when_ to use it, and probably get someone else to do that coding.
In the geek cred hungry world of
BTW, in considering where Woz, Ciarcia, Kahn and Hertzfeld fit into this, I think they are Group 1ers who simply took an interest in Group 2 stuff. If you can learn both mindsets, you are one powerful programming dude, IMO. [Pity that 2ers like myself can't easily (ever?) become 1ers.] Most 1ers just want to get the job done and move on, yet so much can be learned after you think you have finished your program. [MS deserves props for realizing this and assigning a second unit to work on optimizing the code already working -- Win95 crap became slightly less crappy Win98 through this process (pdf)]
I come here for the love
The original post asks if Assembly is still relevant today. I'll ask some rhetorical questions (the only kind in a blog) and see how they apply:
a nalysis/architecture/whatever). The difference is training vs. education.
n dex.html.
* Would you want an astronaut to understand physics and math?
* Would you want a doctor to understand chemistry and biology?
* Should somebody studying to be a Literature teacher take their full set of liberal arts courses, including history?
* Should somebody earning a business degree take music appreciation?
Most of us probably said, "Yes" to most or all of those above. Even if the study seems irrelevant or too "low-level" or too "high-level" at the time, there are areas of coursework that help us understand things better.
I see a lot of dead wood in the IT industry. There are enormous numbers of people who either have no passion or who do not have a deep-enough or broad-enough knowledge of computer science to do their daily data processing job well. They are dependent on others around them for everything, even though they may be very skilled in one area.
By having both a broader and a deeper knowledge, people are necessarily better at troubleshooting and at understanding the areas outside their particular specialty. It makes them be better at all of IT and helps them do their specific role.
You should learn IT two ways -- deeply and broadly. You should deeply learn specific skills (Java/C#/Linux/Windows/scripting in Ruby/whatever) and you should learn broad skills (computing theory/relational databases/networking/troubleshooting/programming/
There is an enormous difference between training and education. Training is learning specific skills for specific tasks (narrow/specific), while education is broader and teaches you how to think, understand, and apply (broad/general).
While taking Assembly may not seem relevant at the time and you may never directly use it again, for every programming task, having a strong background in all of computing theory (including how the CPU handles its low-level instructions) educates you and gives you a deeper understanding. (Don't just be trained, be educated!)
My recommendation is the book My Job Went to India (And All I Got was this Lousy Book). If you can't afford it, read the sample chapters, especially the "Being a Generalist" and "Being a specialist" chapters at http://www.pragmaticprogrammer.com/titles/mjwti/i
Personally, unless you need the specific class/training, I'd say that FORTRAN or COBOL ought to be abolished as required material in all colleges and shouldn't be in the degree program. Those should be electives only. Assembly, on the other hand, should remain required, for a deeper and broader education. (Don't settle for a dumbed-down program).
The difference, again, is training (specific/skill-oriented/task-oriented) vs. education (general/broad/understanding-oriented). Education and being a generalist will reap large rewards, long term. So stick with it and take that class. Assembly is a very important foundation class that educates you, long-term....
Another rhetorical question I have is this: "Are you passionate for IT or is it just a high-paying (presumably) job?" If it isn't a passion of yours, find you passion and do it well. If it is, take Assembly and like it -- it'll help you appreciate IT, your computer, your high-level language, and give you a more educated view of the "soul" of your computer.
(They don't make you take Assembly at many/most schools for their health. It would be a crying shame to remove it from the required courses).
Many different ways.
Using an emulator of a legacy machine would be one way. You could also use evaluation kits for various microcontrollers ('51, ARM, PIC, AVR, whatever suits you best). They have the added bonus that you're running on actual hardware. You could also try a processor simulator, which comes with many uC/DSP development kits.
Say I would learn 68000 Assembler, would that knowledge be much useful when switching to x86?
Yes, because you have already mastered the concepts behind assembly (registers, processor flags, pointers, etc). A different processor may have different rules, but the concepts stay the same. Some of the rules are the same on many architectures ("If the processor has a zero flag, then counting down in loops is preferable to counting up.", for example). Mnemonics and Opcodes are something you just look up in the documentation.
In my current job I spend the majority of my time looking at stress failures (either crash dumps or live remotes), some of which were on production servers running optimized builds. In order to effectively debug these kinds of failures you really need to understand the following:
Ok so I guess some of isn't directly related to assembly, but it is in the same spirit other people have pointed out which is to know how things work under the hood.