low-level Questions
4
Solved
I know in linux it is as simple as /dev/sda but in Windows how do you open a disk and start reading data at the low level?
In python I've tried:
f = open("K:", "r")
and I get this error:
Trace...
8
Solved
Any portable code that uses bitfields seems to distinguish between little- and big-endian platforms. See the declaration of struct iphdr in linux kernel for an example of such code. I fail to under...
Vinitavinn asked 18/5, 2011 at 10:50
11
Solved
Is it possible to divide an unsigned integer by 10 by using pure bit shifts, addition, subtraction and maybe multiply? Using a processor with very limited resources and slow divide.
Thespian asked 5/4, 2011 at 21:4
0
I'm developing a static freestanding nolibc/nostdlib program for Linux and would like to use the C compiler's memory, address and undefined behavior sanitizers to improve my code.
I couldn't get it...
Buckie asked 19/12, 2023 at 23:11
1
Solved
I already learned that on the x86-64 platform using any 64-bit register would need a REX prefix, and any address less than 64 bits would require an address-size prefix.
On x86-64 bit:
E3 rel8 is jr...
3
I need help in associating PHYSICAL_MONITOR which i get from GetPhysicalMonitorsFromHMONITOR with monitors DISPLAY_DEVICE.DeviceID (e.g. "\?\DISPLAY#GSM59AB#5&932a802&1&UID261#{e6f...
Averroes asked 26/7, 2020 at 1:25
1
Solved
I found that we can build/reconstruct an external pointer from a memory address, see this example where I take a pointer from a data table object and rebuild it:
# devtools::install_github("ra...
25
Solved
A friend and I are going back and forth with brain-teasers and I have no idea how to solve this one. My assumption is that it's possible with some bitwise operators, but not sure.
5
This is a follow-up to my question yesterday:
CMS kindly provided this example of using bitwise operators to add two numbers in C:
#include<stdio.h>
int add(int x, int y) {
int a, b;
do ...
1
3
I read a little bit and I find out that SSDT hooks using drivers in Windows 7 x64 systems are harder, on purpose because of Patch Guard/Driver Signing while in x32 systems that doesn't happen.
So,...
5
Solved
I'm facing a quite tricky problem. I'm trying to get 2 virtual memory areas pointing to the same physical memory. The point is to have different page protection parameters on different memory areas...
5
Solved
Which version is faster:
x * 0.5
or
x / 2 ?
I've had a course at the university called computer systems some time ago. From back then I remember that multiplying two values can be achieved with com...
Saval asked 19/10, 2012 at 15:2
1
Solved
When we run a code, the compiler after compile "detects" the necessary amount of Stack memory? And with this, each program has its own "block" of stack memory.
Or the stack memo...
Marchpast asked 18/10, 2021 at 23:52
1
Solved
When setting the mstatus.mpp field to switch to supervisor mode, I'm getting an illegal instruction exception when calling mret. I'm testing this in qemu-system-riscv64 version 6.1 with the riscv64...
3
Solved
I cannot really find anything interesting concerning this question, but I've been wondering for quite some time now how timers and delays in any programming language work at low level.
As far as I...
3
I try to dive deeper and understand the differences between Public | Private | Protected in a low level perspective, in C++.
How are the differences between the three expressed in the memory?
Dieldrin asked 8/12, 2020 at 13:27
2
Solved
I just implemented a Linux command shell in python using only the os library's low level system calls, like fork() and so on.
I was wondering how I can implement a key listener that will listen for...
2
Solved
I read this article about some low level underpinnings of C/C++, and the author is basically showing us through the assembly code generated by the compiler, line by line. He is using VS 2010, but I...
Score asked 8/3, 2012 at 14:28
11
Solved
I've seen a few questions and answers regarding to the endianness of structs, but they were about detecting the endianness of a system, or converting data between the two different endianness.
Wha...
Brickey asked 18/7, 2011 at 11:21
2
Solved
Was reading the MDN docs regarding Wasm. They used the term WASM module quite a few times. Their definition was the following:
A WebAssembly.Module object contains stateless WebAssembly code tha...
India asked 5/10, 2018 at 20:28
1
I get what typecasting in C is doing at a high level. I get that sometimes this is done implicitly, and sometimes is required to be done explicitly. However I don't know how this is happening in lo...
1
Solved
The official documentation as well as tons of articles on the internet say that 'some string' is a primitive value, meaning that it creates a copy each time we assign it to a variable.
However, th...
Pedant asked 25/4, 2020 at 15:4
7
Solved
I'm trying to get a deeper understanding of how the low level operations of programming languages work and especially how they interact with the OS/CPU. I've probably read every answer in every sta...
Ewers asked 1/6, 2014 at 15:27
2
Solved
Consider the following example taken from Wikipedia, slightly adapted, where the steps of the program correspond to individual processor instructions:
x = 0;
f = 0;
Thread #1:
while (f == 0);
p...
Petition asked 6/12, 2019 at 17:31
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