FORUM PAGE (Post your queries here)

  • Trackback are closed
  • Comments (45)
    • prabhu
    • November 26th, 2010

    Greate… Work yaar. Its really interesting to see here to post linux related concept. All the best….

  1. answer me

  2. They are an instruction to the compiler to emit instructions that will cause branch prediction to favour the “likely” side of a jump instruction. This can be a big win, if the prediction is correct it means that the jump instruction is basically free and will take zero cycles. On the other hand if the prediction is wrong, then it means the processor pipeline needs to be flushed and it can cost several cycles. So long as the prediction is correct most of the time, this will tend to be good for performance.

    Like all such performance optimisations you should only do it after extensive profiling to ensure the code really is in a bottleneck, and probably given the micro nature, that it is being run in a tight loop. Generally the Linux developers are pretty experienced so I would imagine they would have done that. They don’t really care too much about portability as they only target gcc, and they have a very close idea of the assembly they want it to generate.

    These are macros that give hints to the compiler about which way a branch may go. The macros expand to GCC specific extensions, if they’re available.

    GCC uses these to to optimize for branch prediction. For example, if you have something like the following

    if (unlikely(x)) {

    return x;
    Then it can restructure this code to be something more like:

    if (!x) {
    return x;

    return x;
    The benefit of this is that when the processor takes a branch the first time, there is significant overhead, because it may have been speculatively loading and executing code further ahead. When it determines it will take the branch, then it has to invalidate that, and start at the branch target.

    Most modern processors now have some sort of branch prediction, but that only assists when you’ve been through the branch before, and the branch is still in the branch prediction cache.

    There are a number of other strategies that the compiler and processor can use in these scenarios. You can find more details on how branch predictors at Wikipedia:

    • seshu
    • December 24th, 2010

    hi can you guide me in installing C in windows vista. i am facing problems with older versions like unable to get full screen of work space etc.

      • prabhu
      • December 24th, 2010

      Use the key ctrl+ for maximize the window size.

      If not working:
      Just check with your operating system architecture and install corresponding package. I hope 16 bit turbo c will work with vista.

      Otherwise you can also use gcc in windows with some modification.

      • devendra
      • February 1st, 2011


      and get the devcpp ide and install it.

      its a great one to work in windows and its having more flexible environment too.

  3. I just want to say Hi to Everyone!

    • prem
    • January 18th, 2011


    • devendra
    • February 1st, 2011

    Hello all,

    here i just wanted to say about some simple concepts about the universal bootloader.

    universal bootloader U-boot is mainly used in embedded systems as u all guys know it because of its more confiurability and many bootable options.

    u can think of u-boot as a miniature operating system which will detect board configurations and sets up board for initial kernel loading procedures.

    Thanks to all,

    I will post new data about u-boot as early as possible.

    Thanks sandipan for preparing this website 🙂 .

    • Thanks for your new topic..
      U are always welcome..

      Anyway will you elaborate a bit on MINIATURE OPERATING SYSTEM 🙂


    • devendra
    • February 1st, 2011

    Hello all,

    The u-boot source consists of a board specific code,
    bootup code,
    cpu instructions (not fully)
    libraries for the specific architecture
    networking code
    user commands to access the board hardware

    The board specific code performs the initialisation of the hardware registers and devices like ethernet, memory and cpu chips.

    The libraries contains apis that are used by most of the functions in the u-boot environment.

    The networking code implements a simple networking protocols like tftp, ping and even nfs.

    through tftp u can load the kernel image and rootfs from a device connected to the board through the ethernet.

    the simple flashing of the board will contains copying of the kernel image in a temporary location, erasing the flash address with the size of kernel image, copying the kernel image to the flash using the cp.b command.

    just as the kernel image the rootfs will be flashed in the same manner.

    u can check the data what the memory contains using md 0x01010101.

    u-boot supports the command line arguments like u can specify some of ur commands in the u-boot.

    like setenv loadkernel=’tftp 0x600000; bootm 0x600000′
    and u can run this command loadkernel using
    run loadkernel.

    this command will start the kernel from the ram.

    thanks to all,

    • devendra
    • February 9th, 2011

    A simple userspace timer

    1 #include
    2 #include
    3 #include
    5 main(int a, char **v)
    6 {
    7 int val;
    8 double diff;
    9 struct timeval tv, tv1;
    10 gettimeofday (&tv, 0);
    11 if ((a == 1) || (a > 2)) {
    12 printf(“usage ./timer timerval\n”);
    13 return;
    14 }
    15 val = atoi(v[1]);
    17 while (1) {
    18 gettimeofday (&tv1, 0);
    19 diff = ((int64_t)(tv1.tv_sec – tv.tv_sec) *

    1000 + (int64_t)(tv1.tv_usec – tv.tv_usec)/1000.0);
    21 if ((diff) >= (float)val) {
    22 printf(“%f\n”, diff);
    23 memcpy (&tv, &tv1, sizeof(struct timeval));
    24 printf(“event\n”);
    25 }
    26 }
    27 }

  4. Such a well written post.. Thnkx for sharing this post!

  5. Good day, A really occupying document. Continue it up.

  6. hello there and thank you for your information – I’ve definitely picked up anything new from right here. I did however expertise several technical issues using this site, since I experienced to reload the site many times previous to I could get it to load properly. I had been wondering if your hosting is OK? Not that I am complaining, but sluggish loading instances times will very frequently affect your placement in google and could damage your high-quality score if ads and marketing with Adwords. Anyway I am adding this RSS to my e-mail and can look out for much more of your respective interesting content. Ensure that you update this again soon..

  7. Terrific post however , I was wondering if you could write a litte more on this subject? I’d be very grateful if you could elaborate a little bit further. Thanks!

  8. hi, solid web log, just I don’t see how to add your site in my rss reader. Could are Assist me please?

  9. I wanted to thank you again for that amazing web page you have made here. It really is full of useful tips for those who are genuinely interested in this specific subject, especially this very post. You’re really all so sweet plus thoughtful of others plus reading your site posts is a great delight in my experience. And such a generous reward! Jeff and I usually have fun making use of your points in what we should do in the future. Our collection of ideas is a kilometer long so your tips will certainly be put to very good use.

  10. Wonderful beat ! I wish to apprentice while you amend your web site, how could i subscribe for a blog website? The account helped me a acceptable deal. I had been a little bit acquainted of this your broadcast offered bright clear idea

  11. You really make it seem so easy with your presentation but I find this matter to be actually something that I think I would never understand. It seems too complicated and very broad for me. I’m looking forward for your next post, I’ll try to get the hang of it!

  12. I just book marked your blog on Digg and StumbleUpon.I enjoy reading your commentaries.

  13. This is really a really beneficial read for me, Must admit you happen to be 1 in the best bloggers I ever saw.Thanks for posting this informative article.

  14. Hi. I wanted to drop you a fast observe to express my thanks. Ive been following your weblog for a month or so and have picked up a ton of fine info and enjoyed the tactic youve structured your site. I’m attempting to run my very own weblog however I think its too basic and I need to concentrate on quite a lot of smaller topics. Being all issues to all folks is just not all that its cracked as much as be

  15. My developer is trying to convince me to move to .net from PHP. I have always disliked the idea because of the expenses. But he’s tryiong none the less. I’ve been using Movable-type on a number of websites for about a year and am concerned about switching to another platform. I have heard excellent things about Is there a way I can transfer all my wordpress posts into it? Any help would be greatly appreciated!

  16. Hi I like your comment and it is so informational and I am gonna save it. One thing to say the Superb analysis this article has is greatly remarkable.Who goes that extra mile these days? Well Done.. Just another suggestion you shouldget a Translator Application for your Worldwide Audience .

  17. Thanks for givingsuch great information. I really likeyour professional approach.

  18. I don’t accept this post. However, I did researched with Bing and I’ve found out that you’re right and I seemed to be thinking in the improper way. Keep on publishing top quality material such as this.

  19. Perfect article we need to spread the word about this website.You need to have extra recognition .

  20. In this grand design of things you’ll secure a B+ for effort and hard work. Where you confused us ended up being in the particulars. As it is said, the devil is in the details… And it could not be much more accurate right here. Having said that, permit me say to you exactly what did do the job. Your article (parts of it) is definitely really powerful which is possibly why I am making the effort in order to opine. I do not really make it a regular habit of doing that. Second, although I can easily notice a leaps in reason you make, I am not really sure of how you seem to unite the details which in turn help to make the final result. For right now I shall yield to your point but hope in the foreseeable future you actually link the dots better.

  21. Its like you read my mind! You seem to know so much about this, like you wrote the book in it or something. I think that you can do with some pics to drive the message home a bit, but other than that, this is excellent blog. A fantastic read. I will definitely be back.

  22. Great stuff mate! Thx@!

  23. hey there and thanks in your info – I have definitely picked up anything new from right here. I did on the other hand expertise a few technical points using this web site, as I skilled to reload the website lots of occasions previous to I may just get it to load correctly. I were considering if your hosting is OK? Not that I’m complaining, however slow loading cases times will very frequently affect your placement in google and can harm your high quality ranking if ads with Adwords. Anyway I am adding this RSS to my email and can look out for a lot more of your respective exciting content. Make sure you update this once more soon.

  24. Hello I absolutely dig this post and it has been too marvelous therefore I am gonna save it. I Have to say the exceptional analysis you have done is trully extraordinary !! Who does that additional research now days? Hats off to You !!! Just one more tip you definetlyinstitute a Translator Application for your Worldwide Audience !!!

  25. Hi I definetly dig this story and it was too superb thus I am going to tweet it. I Have to say the Superb analysis this article has is trully exceptional . No one goes that extra mile now days? Hats off to You ! Just another suggestion you shouldinstall any Translator for your Global Audience 🙂

  26. It´s about fitness mates! Or whatrrrs your opinion? I like this info and possesses presented me some sort of commitment to succeed for reasons uknown. Furthermore I´m definitely considering writing these figures in my own blog!

  27. sir it’s nice to see a page containing linux .it’s great keep it on just try fill it more & more . and come online we will discuss more about it

  28. I have been exploring for a little bit for any high quality articles or blog posts on this kind of area . Exploring in Yahoo I at last stumbled upon this site. A href=””>Fundacja Reading this information So i am happy to convey that I’ve a very good uncanny feeling I discovered exactly what I needed. I most certainly will make certain to do not forget this web site and give it a glance on a constant basis.<

  29. Purely to follow up on the up-date of this issue on your web page and would wish to let you know just how much I loved the time you took to put together this handy post. Inside the post, you really spoke on how to seriously handle this challenge with all comfort. It would be my personal pleasure to collect some more ideas from your site and come up to offer people what I learned from you. I appreciate your usual great effort.

  30. Hi, I am searching for another hosting company. Could you recommend a good one? I would sign up by using an aff link from you. Thanks. ^^

  31. Great article. Thank you for creating my own full week.

  32. Audio started playing any time I opened this web site so frustrating

  33. Allison_Lynn_A

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: