Programming :: Memcpy Fails To Copy Data / But Byte By Byte Assignment Work
Jul 6, 2011
I got across a peculiar problem with memcpy.History:writing a code which do flash/Read functionality for SPI Parts.
Implementation:
1.memory map the Flash chip registers to userspace. - fine
2.Issue block read command
3.Just print the data I got, using the memory mapped address - fine I got the correct data.
4.Copy the data to a local buffer from memory mapped address using memcpy - FAIL
UPDATE:
on SUSE 11.3 -32 bit the above code worked perfectly, but on SUSE 11.4 - 64bit , Ubantu, Fedora it failed.
I am using gcc compiler obviously. I am using i386/x86_64 OS. Processor: Intel core 2 duo, SNB after step 4 , when I dump the data from local buffer every thing is FF.But step 4, if i implement byte by byte copy using assignment operator, it worked.is there any known bug with memcpy? am I missing anything?
At present I have to live with a 5Gb/month data volume limitation. Due to having to monitor this usage, I have been forced to use the software that came with the web dongle - and that means having to use Windows (spit!)
Can anyone recommend a Linux package I could download that readily shows how much data one has uploaded/downloaded over a set period?
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Code:
#include <stdio.h> #include <math.h> main (int argc, char* argv[]) {
In words, AND the byte at memory location 45 with immediate value 03. As reports "Ambiguous operand size for and". How could I code the instruction such that as understands my intention?
john: .byte 45 and byte[john],03 gives the same error.
I'm trying to write an extension to PHP which means coding in C. I'm really really rusty at C coding and was never very good at it.
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global asm_strlen section .data section .bss section .text
[code].....
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So I do df -B 4096 and it reports this result:
Code: Filesystem 4K-blocks Used Available Use% Mounted on /dev/sda1 15618840 13190294 1635137 89% /
But when I use dd to go past that block, it doesn't report an error or anything. The command I'm using is
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I have a file that stores employee login IDs, names, types, and permissions. Our software reads the information based on byte-columns, so it reads a column as any ASCII character (spaces, letters, numbers, punctuation, etc.). I want to create a web-interface for adding and removing users, and storing the data in a MySQL database. However, if I am creating the files from the MySQL output, I need a way to write to specific column locations in the file ...
User ID: Columns 1-4 User Name: Columns 6-30 Type: 32-40 Permissions: 42-45
I want to use a scripting language, preferably C-Shell, to call MySQL for the data and write the data to the correct columns of the file. I wrote a script that takes the data from the file, and dumps it into the MySQL table, so maybe I can pad the remaining space in the table column to fill with spaces ...
I'm sniffing network packets in ubuntu, I need to write these packets as raw bytes to memory but libpcap give packets in its special format. how can i save and recover packets in byte format?
does the assignment operator copy all the members also for structures containing STL objects strings,vectors,vectors of vectors...)? I did try it on my platform,and it works that way (copying all the fields),but i was wondering if it is a standard behavior or not.
I have to get soem statistic about interfaces from /proc/net/dev. but statistic on this file is reset when get reach more than 4G byte.I think linux has limitation on this case.
I am getting a new 4kb sector HDD for my laptop, WD scorpio black 750gb, I would like to image existing partitions on 512bytes sector HDD and move them to the new 4kb sector HDD, what's the best way to do this.
present config is as follows:
Disk /dev/sda: 80.0 GB, 80026361856 bytes 255 heads, 63 sectors/track, 9729 cylinders, total 156301488 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes
[Code].....
I am planning to keep the same three partitions as the primary partitions on the new drive and add few more logical partitions. I would have liked to move to GPT but since I need Win 7, I am stuck with MBR partiotion table.
Now, I understand how to partition an Advanced format disk, what I want to know is how to move the existing partitions on the 80 Gb disk to the new disk?
I use Clonezilla to copy partitions but it is not compatible unless both the target and the source disks are already using 4096 sector size.
I can use Acronis True Image WD Edition to clone Win 7 but how do I clone Ubuntu?
Also my Laptop's chipset is limited to SATA 1.5, will it cause any issues, I know the bandwidth is not an issue.
I'm I seeing this wrong or is the initrd file in kernel-2.6.27.25-170.2.72.fc10.x86_64 a zero byte file and that's why I can't boot with it( get this "kernel panic not syncing VFS unable to mount root fs on known -block (0,0)" message)
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Second, these object don't really have a "type", they're just containers that contain any values you want under any name you want. How can I, for example, define a primitive "boolean" object and have things like if statements recognize it?
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it's been a long time since I did coding in C, but thought to pick up a very old project again, just to show off what I have been working on ten years ago.I deducted my problem as follows:
