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26,778 questions
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0answers
9views
Compiling error with the Intel Math Kernel Library (MKL) on Linux when running cmake
I am having some issues after installing the MKL library on my Linux Intel machine (Intel(R) Xeon(R) CPU E5-2650 v4 @ 2.20GHz). When I run cmake, I get the following error:
[ /home/278926k/GSM/...
- 93
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0answers
11views
What is root complex vs System agent in a x86 architecture?
In the x86 architecture, what is term root complex and system agent?
I guess, System agent is basic barebone base foundation of SOC, on top of this many other buildinf blocks like Memory controller, ...
- 11
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0answers
11views
TBB Combiner Node Implementation
Is there a way to implement a tbb node that combines the output of multiple nodes (the number is known at run time but not at compile time) into one vector or tuple?
Suppose I have Node1, Node2, .., ...
0votes
0answers
31views
How to quantify the depth from a depth image correctly
Input
I have this depth image of type uint16 obtained from Intel realsense L515 camera.
Goal
I want to quantify the depth of the blocks inside this image to get a discrete representation of the blocks ...
- 2,342
0votes
1answer
32views
Faulty benchmark, puzzling assembly
Assembly novice here. I've written a benchmark to measure the floating-point performance of a machine in computing a transposed matrix-tensor product.
Given my machine with 32GiB RAM (bandwidth ~37GiB/...
- 135
0votes
0answers
19views
EPT violations through speculative execution
Can speculative execution cause an Extended Page Table (EPT) violation on x86 processors?
Assume I want to access a structure that has different Guest Physical Address (GPA) to Host Physical Address (...
- 848
0votes
1answer
27views
Assembly language code is giving inaccurate results. (8086 emulator)
I need to write a code in 8086 emulator where a user gives an input from 0 to 9. If the value is below 3, 'Good morning!' is printed. If the value is greater or equal to 4 and less than 6 (just 4 and ...
- 1
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0answers
12views
How do I print the first 100 numbers of a multiplication table of a 3-digit value?
So I'm new to assembly language (Being honest, It's still confusing to me) and I need to make a multiplication table code for 3-digit numbers in assembler. This program needs to multiply as many times ...
0votes
0answers
27views
Modulo, align_up function assembly code x86
I have the following generated assembly code that keeps crashing for some reason.
0000000040001AF0: 48 8D 44 24 30 lea rax,[rsp+30h]
0000000040001AF5: 48 89 08 mov ...
- 1,204
3votes
1answer
69views
Is it still worth using the Quake fast inverse square root algorithm nowadays on x86-64?
Specifically, this is the code I'm talking about:
float InvSqrt(float x) {
float xhalf = 0.5f*x;
int i = *(int*)&x; // warning: strict-aliasing UB, use memcpy instead
i = 0x5f375a86- (...
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0answers
23views
Problems accessing a _Thread_local variable in x86_64 asm
I my currently working on a project that involves asm x86_64 and instrumenting code. I insert asm code thru GIMPLE that allow me to access a variable by name and decrease it. For example: sub $%d, ...
-1votes
0answers
21views
.Netcore profiler crashing
I have developed my own .NET core profiler using VS 2019. To load my profiler, I have set the environment entry in the web.config file.
<environmentVariable name="CORECLR_ENABLE_PROFILING"...
0votes
1answer
51views
How to get time in milliseconds in assembly?
I was able to get it in seconds, but how to get the value of milliseconds?
I am trying with the gettimeofday system call:
sys_gettimeofday_ms:
enter $0, $0
pushq $0
pushq $2
leaq -16(%rbp), %...
1vote
1answer
41views
Difference between __builtin_addcll and _addcarry_u64
Good morning (or good evening),
I was reading some legacy code in my company and I found the following intrinsic was used:
_addcarry_u64
However, I have to port this code on a platform that does not ...
- 13
1vote
0answers
36views
windbg kernel debugging - How to get the physical address
I have a module loaded at fffff801`16e00000 and want to get its physical address via !pte but windbg is saying "Levels not implemented for this platform", what gives?
I know how to do i ...
- 143
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0answers
18views
I am doing a Stack-Based Overflow and having a hard time figuring out how to overflow it exactly the right amount
I am doing my university cybersec website because I want to get better at it and right now I'm working on a challenge that involves having to connect to a server, which promps me for input using C's ...
- 3
0votes
0answers
29views
Difference between `shl di` and `shl di, 1`
I tried to compile the following with NASM
shl di
which, according to this very non-sketchy source should multiply di by 2 once. However, I get an "invalid combination of opcode and operands&...
- 2,922
1vote
1answer
19views
Setting Package-Wide MSRs for Uncore Frequency and Cache Allocation Technology
I am trying to set way masks for different class of service (COS) on an Intel Xeon processor.
I am using the following command to make COS0 use all but the last four cache ways:
sudo wrmsr 0xc90 0x7f0
...
- 105
0votes
1answer
31views
How do I print multiple variables in assembly x86?
I'm trying to print "varc1", "varc2" and "varsm" on the screen but after printing the first variable my program gets into a weird loop. I copied the code related to the ...
- 81
2votes
1answer
30views
How does the Dirty and Access bits affect the TLB?
I get it that if a page has been accessed it'll have the Access bit set, and if has been written to, the Dirty bit will also be set. But it's unclear to me how these bits affect the TLB/TLB caching? ...
- 143
0votes
0answers
39views
openmp memory leak when using g++ and Intel's libiomp5
I found this code:
#include <iostream>
#include <vector>
template<typename T>
void worknested1(std::vector<T> &x){
#if defined(_OPENMP)
#pragma omp parallel for num_threads(...
- 323
0votes
0answers
20views
Access violation reading location 0x04106011, I can't tell where is wrong
; 2.Linking Array Items
.data
start dword 1
chars1 byte 'H','A','C','E','B','D','F','G'
links DWORD 0,4,5,6,2,3,7,0
target byte lengthof chars1 dup (?)
.code
mov edi, 0
mov ecx,...
- 1
1vote
0answers
30views
Confusing results on CHA aware Jacobi 2D microbenchmark
I aim to implement a lower latency version of jacobi 2d stencil. The default version is depicted below in the code snippet:
for(auto i = 1; i < N - 1; ++i) {
for(auto j = 1; j < N - 1; ++j) {...
- 162
0votes
1answer
31views
Trying to compare input of '+' with its ASCII value of 43
I'm new to writing posts with code imbedded in them so give me a break if this looks terrible, or suggestions on how to make it look nicer. :)
The issue I'm having is pretty much what the title says. ...
- 1
-1votes
0answers
53views
Files extensions and there meaning when building a C++ project
Could please someone explains to me in details :) what are the files .lib, .exe, .dll, .pdb, .log, .exp, .idb. generated after building a C++ project.
Thank you!
0votes
1answer
38views
How to determine if a value is a character or number in MASM
I'm having trouble with figuring out how to determine if a value is a number or letter in MASM assembly language. This program should go through and array and display the first number found in an ...
- 21
0votes
0answers
15views
assembly language program using Emu80886
The program displays the time in the format:
hour : minutes : seconds
Of the cities of Mexico, London and Tokyo; it updates the hours according to the time of the computer's operating system until ...
1vote
1answer
38views
OpenVINO cannot convert 1D CNN model with model optimizer
I convert my 1D CNN .h5 file to .pb file as the picture shows.
(Please download my converted .pb file in need.)
Then I try to use model optimizer to generate .bin and .xml files with the command
...
- 33
-1votes
1answer
33views
Taking user input and incrementing the number by 1
In this code the user is asked to supply a number.
Once they do so the number should be incremented by 1.
This code works when you hard code the value of the number on line 11 (movq $number , %rsi).
...
0votes
1answer
47views
half_baddata function in c
**what this part of code means and do in c? I can't understand it!**
What's the return value of the if condition and when it will happened?
LAB_001012c5
if(local_10 != *(long*)(in_FS_OFFSET + ...
- 1
0votes
0answers
19views
Printing out hello world with assembly
I had just started to learn assembly and some lower level concepts (I have some higher level background with python, js, etc).
I am trying to print out hello world with the following assembly program:
...
- 11
0votes
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15views
Compare statement not working with User Input in assembly language x86 nasm linux
I am trying to create calculator in x86 assembly language, I am taking input to check which operation user wants, but cmp statement is not working. After taking input program directly jumps on ...
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0answers
21views
Cannot seem to increment users input by +1 and print it back out to the screen x86 Assembly, AT&T syntax 64bit registers
So, I have attached my code below which basically asks a user for a numerical input, once the users supplies the number the code should add 1 to it and print it back out to the screen. However, this ...
0votes
0answers
25views
Intel MKL API's replacement for ARM
I am building an x86 CPP project for ARM64 but the x86 project has a few Intel MKL APIs which are not supported for ARM is there any equivalent ARM64 replacement for these below listed MKL APIs?
...
- 21
0votes
1answer
61views
how to call assembler code with Python on Windows
this link gives a good example to execute asm with Python on Linux platform, but I dont know how to call an asm func with return value on Windows, Could you please tell me how to do that or give me an ...
- 21
0votes
0answers
25views
How to make the if else here?
%include "asm_io.asm"
global main
segment .data
msg1 : db "somme-nous samedi?",10,0
msg2 : db "Bonne weekend",10,0
msg3 : db "Bonne ...
0votes
1answer
71views
How stable / constant is the timestamp counter (RDTSC) with temperature and over time?
x86-CPUs have invariant TSCs for a long time, i.e. they change the timestamp counter according to a constant frequency, usually the base-clock of the CPU.
If Windows detects an invariant TSC it ...
- 1,987
0votes
2answers
31views
Opening file modes in x86 assembly Linux
I'm learning x86 assembly Linux from the book Programming from the Ground up, currently I'm learning how to open a file and read or write to it. I'm having trouble with the options for opening files, ...
- 163
0votes
0answers
39views
Can't set the higher half of ymm registers
I'm trying to extend the word values from the lower half of the ymm0 register into the lower and higher half of it. When I execute the vpunpcklwd instruction, the higher half of the ymm0 register is ...
- 3
0votes
1answer
56views
Intel NCS2 suddenly disappears adfter multiple successfull inferences
I'm running a Raspberry PI 4B Buster environment with all recommended OpenVino dependencies.
I'm trying to put together an object detection pipeline, with multiple object detectors, and multiple ...
- 1
0votes
0answers
23views
Weird results while capturing single frame with realsense camera
I'm using Intel Realsense L515 camera to capture a single frame as fast as possible.
I have seen this question about setting the exposure manually, and I have taken that into account.
Even though the ...
- 2,342
0votes
0answers
8views
Secure Boot Firmware Keys are not whitelisted?
please see screenshot attached ?
any recommendation ?
Im using: Intel S2600STB and dual Xeon Gold 6154
enter image description here
- 1
0votes
1answer
73views
Getting nan values from OpenCL FFT kernel on FPGA
I was trying to use the Intel's FFT1D kernel by writing the Host program by my own for Intel FPGA. Link to Intel's FFT1d can be found here
I have also given my host program below, wherein, I have a ...
-1votes
1answer
27views
Error while modifying mallocated string in a C struct with asm function
i would like to modify a string inside a C structure with an asm function but it is not working properly...
Let say that i have this type of structure on a 64 bits architecture :
typedef struct ...
- 44
0votes
0answers
25views
Iterate through files in directory in NASM x86
I looked everywhere for any question like this, to no avail.
I am trying to get acquainted with x86 ASM, using NASM in Ubuntu.
I want to write a program targeting only files with a .txt extension, so ...
- 35
1vote
1answer
36views
Why does my string-print function print extra garbage / file contents after the C string I pass it?
I decided to make a function that prints a string in the EAX register to the console, works from a part by displaying a message first, then something
Code (NASM) :
newLine equ 0xa
section .data
...
1vote
1answer
71views
Does Windows map DLLs to the same virtual address in different processes?
Say two processes are using Kernel32.dll, does Windows map the DLLs to the same virtual address space in both processes? If not, how does paging mechanism end up using the same physical address where ...
- 143
1vote
1answer
105views
x86 assembly language integer "cube root" with Newton's algorithm
I'm writing a program that calculates the cube root of an unsigned 8-bit integer.
I'm using Newton's iteration algorithm to determine the cube root of perfect cube numbers like 1, 8, 27, 64, 125, 216, ...
- 11
0votes
1answer
34views
why sometimes use offset flat:label and sometimes not
I'm learning assembly using GNU Assembler using the Intel syntax and there is one think that I don't really understand. Say for example this code right here :
.intel_syntax noprefix
.data
string: ....
- 27
0votes
0answers
26views
How do I do addressing in NASM 64-Bit mode right (compiler doing strange stuff)t?
I'm trying to code an OS and every thing went well until here. I'm in Long-Mode and my 'kernel' code is executing if I pagemap it to an address that's 32-Bit. But if i don't do that my kernel stops ...
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