how to perform floating point operations in kernel? i answered that its impossible to perform floating point operations in kernel.but he is telling that its possible but with some feature to be added.can any body know about this perfectly??
View 1 RepliesI have tried to learn how 64bit asm (nasm in my case) works and found, among the many disparate pieces of info on the net, a few vague inferences that floating point registers can be used for other purposes than what they are intended for, example: "64-bit Linux allows up to fourteen parameters to be transferred in registers (6 integer and 8 floating point)." This would be fantastic for string operations/manipulation (I have never used asm for floating-point operations), can anyone shed a bit of light?
View 8 Replies View RelatedI am dealing with money and I don't want it to show $.1, I'd rather it show $.10 Is there a way to change this in C++?
View 4 Replies View RelatedI know it is wrong to use the "==" operator to compare the equality of two floating point numbers. Logically it would seem that if the "==" operator is not usable for floating point comparison, then the "<=" operator would also not be usable. Is this true? The lack of google search results on this topic made me think that it must be true. If that is true, then is it true that the only way to compare floats with <= or >= is with something like the code below? Code: bool smaller_than_or_equal(float a, float b) {
if ( fabs(a-b) < EPSILON){return true;}
else if (a < b) {return true;}
else {return false;}
} I think this is a general question, but if specifics are necessary, I am using the C++ language to code at the moment.
I'm reading a book on assembly, and it talks a bit about the IEEE floating point format.
Quote:
To summarize, the following steps are used to convert a decimal number to IEEE single format: 1. The leading bit of the floating point format is 0 for a positive number and 1 for a negative number. 2. Write the unsigned number in binary. 3. Write the binary number in binary scientific notation f23.f22 ... f0 2^e, where f23 = 1. There are 24 fraction bits, but it is not necessary to write trailing 0's. 4. Add a bias of 127 to the exponent e. This sum, in binary form, is the next 8 bits of the answer, following the sign bit. (Adding a bias is an alternative to storing the exponent as a signed number.) 5. The fraction bits f22f21 ... f0 form the last 23 bits of the floating point number. The leading bit f23 (which is always 1) is dropped.
I am getting error Fortran runtime error: Bad value during floating point read. How do I format negative sign?
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I have a .txt file with the format
0.01
0.04
0.07
...
0.83
I am wanting to load this into octave and perform operations on the data.
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I have got fedora 13 install on my system. I wanted to know how could I perform scandisk and defragmentation like operations in linux?
View 5 Replies View RelatedMy main problem right now is doing floating point arithmetic within a bash script, with variables.Right now I have a folder called "myExamples" with a script called "run_example" that runs with no issues.I plan to(1) create many folders inside [myExamples], that are named [example10] [example11]...each containing an identical copy of (run_example),(2) modify Line 172 of each copy of (run_example)...in one copy, it would be 3.00, the next copy would have 3.05, etc. (This part doesn't work!)How can use the available calculator bc code to do floating point operations?My code is below -
#!/bin/sh
# run from directory where this script is
cd `echo $0 | sed 's/(.*)/.*/1/'` # extract pathname
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We all know linux kernel base layer is made up of structures, in which every object of kernel is well defined. Structure members correspond to object properties required to define object behavior.
For example if we take case of File system.It composed of four objects , superblock objects, inode objects, file objects and dentry object.Each having well defined structure which is being operated by system call handler and by system call service routine in the kernel mode.
Now my question is even in kernel mode we do not have some mechanism by which we can get access to pointer of these structures.We have some macro.
If I want to manipulate structure on my on way, or performing some more operation defined by me.For example after the crash of Hard Disk Drive, having ext2/3 file system, If i want to know all the inode pointers, and block details.
Can I have some way out to do desired operation ??
mechanism to operate on these base label structures, even in kernel mode ..
pidgin started crashing today for no apparent reason. It just shutdowns. No freezing or anything, it just goes away, disappears. From what I can say, there's no specific trigger for this, it can happen after 2 or 10 min after I started it. Once it even shutdown right 10seconds. I tried to run it from the terminal. When I do that, the only thing that appears before closing is
Code:
Floating point exception Anyone has an idea of what it can be? I made no upgrade to pidgin or libpurple recently. I made however an upgrade today of the following packages
Code:
Commit Log for Thu Feb 18 10:24:00 2010
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I am facing floating point exception issues in running top on some of my Red-Hat Linux servers
# top
6:45am up 476 days, 52 min, 4 users, load average: 0.00, 0.00, 0.00
109 processes: 108 sleeping, 1 running, 0 zombie, 0 stopped
Floating point exception
When I am executing the same command using strace or ltrace, its running fine.
# ls -lrt /usr/bin/top
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I am using a gateway server, 1st NIC eth0 which is acting as WAN (DHCP)and 2nd NIC acting LAN(static). I am using DHCP to assign IP to eth0 from a Wimax modem. I am also use it as a MAIL server (openmail), and as a DHCP server. My server is of RHEL and kernel version is 2.4.8.18-14 and DHCP client & server version - 30pl1-9. The prolem is whenever I run the command..
ifup eth0
getting the error...
Determining IP information for eth0.../ifup: line277: 23328 Floating point exception/sbin/dhclient ${DHCLIENTARGS} ${DEVICE}
so what should I do?? if I update the DHCP, would it be ok?
games, specifically solitaire and gimp both have started returning a floating point exception fault.
View 9 Replies View RelatedI had fuzzy icons in system tray so before couple of days i installed some updates and after that i have floating point exception in ktorrent and virtualbox 2.6.34.7-0.7-desktop #1 SMP PREEMPT 2010-12-13 11:13:53 +0100 i686 athlon i386 GNU/Linux
nvidia 9500 GT
X.Org X Server 1.8.0
KDE 4.4.4
Here is the updates
nvidia-gfxG02-kmp-desktop-260.19.21_k2.6.34.0_12-19.1 Tue 04 Jan 2011 04:14:42 PM CET
x11-video-nvidiaG02-260.19.21-20.1
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This is the first time I post a question on these forums My problem is as follows: I can't start gnome-terminal from the Applications->Accesories menu or from the Alt+F2 application launcher. I get a "Starting Terminal" in the task-bar that disappears after a few seconds and no terminal. I'm pretty sure there is something I did, but I can't really figure out what it is.
The things I've tried so far:
1. I used synaptic to remove and reinstall gnome-terminal. That didn't work
2. Started Xterm and tried to run "gnome-terminal". This is where it gets weird for me:
a. running the command as normal user I get a "Floating point exception" error and obviosly no terminal
b. when I do "sudo gnome-terminal" and enter the root password I get, as expected, a root terminal. I could live with that, but it's not ideal.
I put an SD card in a reader, got all the right signs from the kernel (SCSI device: sda; write-through; etc.)including its 2GB size.
When I try to mount /dev/sda1 I get 'floating point exception' as a response, and it won't mount.
I've never had that message returned from mount, and I can't find any reference to it.
One of those odd things I learned the hard way is that if you are writing a shared object (library/.so) and any programs that will link to that library uses floating point numbers, the library must be compiled as if it uses floating point numbers. What that really means is, you need to declare at least one float in the source for the library or when the caller connects and tries to run code in the library, the process aborts.I end up putting a float pi (3.1415); in the code and getting an unused variable warning all the time. There has to be a simpler way, some flag to pass to g++ that says, "include floating point support even if you don't really need to."
p.s. Gosh I hope I remembered this correctly. I encountered this problem doing a multi-platform build for Windows and Linux. This COULD be a VC++ problem that I just carried into Linux by using the same source.
I just loaded octave. I ran through a few examples of how to implement a script file. Everything works until I get to "plot". When I run the "plot" command I get the following.
octave:2> test1.m
error: can't perform indexing operations for <unknown type> type
sh: gnuplot: not found
Just to double check my work, I ran the following code:
y=[1 2 3];
plot(y);
Just updated WinFF to version 1.3.2-1.1. Since then it won't start up any more due to a floating point exeption. System: OpenSUSE 11.4 (x86) + KDE 4.6.0 Debug info:
WARNING] Out of OEM specific VK codes, changing to unassigned
[WARNING] Out of unassigned VK codes, assigning $FF
ERROR in LCL: TLRSObjectReader.SkipValue unknown valuetype
Creating gdb catchable error:
$080D1568
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I had the same error with earlier versions of WinFF in earlier versions of OpenSUSE. Then I could fix it by changing the KDE window styles. The error also occurs with the WinFF qt-version.
Over the last few months there have been multiple updates and I am getting a list of things that no longer work or that cause my system to fail. I can no longer open a pdf in firefox. It says there is no application assigned to the task. I ran evince and tried to open a pdf file and received a "floating point" error message on the terminal screen I was working from.
View 1 Replies View RelatedI have been trying to convert a DVD9 to DVD5 using the following steps
1)Rip the DVD title(s) to harddisk with DVD:RIP in a project folder. This created VOB files of the the movie and the soundtrack you picked.
2)Concatenate (merge) the VOB files into one by running in a console: cat *.vob > movie.vob
3)demutliplex movie.vob and get the M2V and AC3 files out of there. tcextract -i movie.vob -t vob -x mpeg2 > movie.m2v
4)tcextract -i movie.vob -a 0 -x ac3 -t vob > movie.ac3
5)I then shrank the movie.m2v tcrequant -i movie.m2v -o shrinked.m2v -f 1.5
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I'm running CentOS 5.4.In the last three days I've started to get various cron errors:
/bin/sh: line 1: 7066 Segmentation fault /usr/local/scripts/cron.email.sshd.access/cron.email.sshd.access.pl
/bin/sh: line 1: 4822 Floating point exceptionsudo -u mobile getmail --quiet
Can't load '/usr/lib/perl5/vendor_perl/5.8.8/i386-linux-thread-multi/auto/RRDs/RRDs.so'
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Then yesterday I rebooted, and all the other errors seemed to have disappeared for now, but, I am now getting:
/bin/sh: line 1: 23600 Segmentation fault sudo -u mobile getmail --quiet
I have setup cron to call getmail once every 3 minutes, and I get this error about 4-6 times an hour.
I ran into this problem myself, and I've seen that others have had the same problem when updating from Karmic to Lucid via apt-get. There is a bug in apt for Lucid, and it has been noted on one of the Ubuntu lists
This is a simple how-to and a work-around to the upgrading with apt-get:
1) Update your sources.list file to replace all instances of 'karmic" to 'lucid' : $ sudo sed -i 's/karmic/lucid/g' /etc/apt/sources.list
2) Run apt-get update: $ sudo apt-get update
3) Run a regular upgrade; $ sudo apt-get upgrade -y
Here is where the problem comes in. Apt is looking for the util-linux package, which is part of upstart-job, but someone apparenlty forgot to write the code to tell apt-about this (whoops!)
So, you now need to install upstart-job by itself. By skipping this step you will get the error message when you try to run step 5: "E: Could not perform immediate configuration on 'util-linux'.Please see man 5 apt"
4) $ sudo apt-get install upstart-job
5) Now you can run apt-get dist-upgrade: $ sudo apt-get dist-upgrade -y
I have recently been getting into kernel development and was wondering whether the Linux kernel or BSD kernel would be easiest for newbies (such as myself). Does anyone know? I am really considering BSD because it seems to me to have the best documentation.
View 2 Replies View RelatedI just Installed Xubuntu 10.04 and as I was using it, the panels dissapeared. I tried running xfce4-panel but I get a "floating point exception" message. what might be causeing this?
View 3 Replies View RelatedI'm trying to compile a Linux kernel module called hello-2.c using the command "make -C /lib/modules/$(uname -r)/build M=${PWD} modules" (without the quotes) (which I found online), and the following is the (seemingly successful) output.:
Code: Select allmake: Entering directory `/usr/src/linux-headers-3.2.0-4-amd64'
Building modules, stage 2.
MODPOST 0 modules
make: Leaving directory `/usr/src/linux-headers-3.2.0-4-amd64'
However, I don't see a hello-2.ko (in the same folder or anywhere else for that matter). I'm Using Debian GNU/Linux 7.6.
Everything I am doing is within a folder/directory called "thefolder" (without the quotes) in the "/tmp" directory (without the quotes).
Why I can't see a hello-2.ko, and what to do to get it?
why installing kde 4.6 from factory repos went wrong ? i used zypper dup with oss, non-oss and update repos for 11.3 to reset to default install and boot went ok :
this goes with the following package versions:
$ kded4 --version
Qt�: 4.6.3
KDE�: 4.4.4 (KDE 4.4.4) "release 3"
i'm using this x86 kernel :
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my problem : when i add factory repos (core and extra) for kde install of packages from yast is ok when switching system packages to these. but after reboot i have floating point exceptions and a black screen and can' t boot anymore. the only way out i found so far is to zypper dup to go back to kde 4.4.4
I tried to install the 2.6.31.12 kernel (as suggested for security reasons) twice, and each time, I got a *BIG* mess up of the installation. Here is the story (I'll try to keep it short): The installation of the kernel was not a problem, it went fine both time (I just had to reorganize Grub entries a bit). At first, all was running normal. Suddenly, after having left the computer idle for a moment, I was faced with a black screen (blanker probably) and I could not wake up the system: no mouse, no keyboard, all seemed to be frozen and I had to press the reset button.
After the reboot, and as soon as the desktop was loaded, I got an error message saying that /var has 0 bytes left ! The nightmare began... The first time that happened, I tried to find what was wrong in /var and /var/log , but found nothing abnormal. The info given by the Diskinfo tool were strange, sometimes showing /var as 100% full, sometimes it was /home that was 100% full and some other times it was /. I tried to fall back to kernel 2.6.31.8 using Yast, but it failed at the middle of the process. At this point I realized that the system was very unstable.
I then booted the Install HD and run the repair mode. Some errors were found and corrected, but in the end, the system was not repaired; and worst, Grub lost all entries except the floppy one. (Hopefully, I knew how to boot the Install HD from Grub's command line). I tweaked again and again, and finally got my system up again with kernel 2.6.31.8 (don't remind all the steps). Recently, as the kernel update was still suggested, as there were other updates in the meantime (like mkinitrd), and as haven read anyone else complaining about 2.6.31.12, I decided to give a try again.
And again, a couple of days later, same symptoms: black frozen screen, no space left in /var. As I knew the system was unstable, I immediately booted the Install HD. Tried the repair mode and it failed (just mess Grub again). Tried to (update) install kernel 2.6.31.8 from there and it also failed. I then started the rescue mode and tried to delete some big files in /var (again I did not found any monstrous thing in there), then tried again the repair and update process with no better results.
From rescue mode, I finally deleted everything in /var (that was not a good idea as I also deleted some NEEDED files)... Got the system to boot, but only to the text login: nscd failed because of missing files in /var, starx failed because no X server found, ... Fed up, I lastly decided to "update" all system base RPM, the Gnome and KDE desktop environment from the 11.2 install HD, then update everything again with Yast Online Update.
How do you do things like list directory contents, mov/copy files, make directoriestc. in C?
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