Questions tagged [bitwise]
Bitwise refers to a bitwise operation which operates on one or more bit patterns or binary numerals at the level of their individual bits.
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1answer
79 views
Division without using division, multiplication, or modulus operators
The task
Implement division of two positive integers without using the
division, multiplication, or modulus operators. Return the quotient as
an integer, ignoring the remainder.
My solution
<...
4
votes
1answer
71 views
Python binary calculator
My task was to build a calculator in Python supporting binary addition etc.
To begin I define a couple of custom exceptions :
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3
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1answer
149 views
Hamming Distance in Python
I was solving this Leetcode challenge about Hamming Distance. Would love feedback on my syntax and code style. Here's the challenge description:
The Hamming distance between two integers is the ...
6
votes
3answers
240 views
Encoding 0/1 bits to 0/255 bytes in C++
I need to map a sequence of bits that represents a float into a sequence of bytes by this rule: the value 1 maps to the value 255 and the value 0 maps to the value 0.
This is the code I have now:
<...
2
votes
5answers
242 views
Largest binary gap
I took a task from Codility to find longest sequence of zeros in binary representation of an integer.
For example, number 9 has binary representation 1001 and contains a binary gap of length 2. ...
3
votes
2answers
97 views
Change Arithmetic Right Shift to Logical Right Shift
The following code is a solution to a textbook (Bryant&O'Hallaron: Computer Systems A programmer's Perspective 2nd Ed) problem in bit-level data manipulation (attempted for the challenge, not a ...
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1answer
30 views
Implementing carryless multiplication using normal multiplication
In carryless multiplication the partial products are XORed (ie addition without carry) together rather than added normally. The partial products themselves are still the product of a power of two (...
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2answers
64 views
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1answer
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2answers
116 views
C bit mask calculator written using GTK+ 3
I've been studying C on my own using K&R 2nd Edition, and started exploring GTK+ to practice some of the concepts I've learned by making GUI applications. This is the first GUI application I've ...
6
votes
4answers
193 views
Efficiently swapping the first and last five bits in an unsigned 16-bit integer in C
I'm programming on an 8-bit Z80 embedded system, and encountered a problem. The program needs to render some pixels to the screen. The color is stored as RGB565 format as a 16-bit unsigned integer, ...
2
votes
1answer
75 views
C++ class for a flag register in a Chip8 emulator
In order to learn C++ I decided to code a Chip8 emulator following a tutorial. When I came across the idea of a flag register and decided it would be fun to implement in order to get familiar with ...
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1answer
62 views
Maximise XOR of two elements
I have a number x and I need to choose another number y from the given range [l, r] such ...
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1answer
49 views
Kademlia bucketing
Kademlia is a DHT (distributed hash table) which uses a specific type of routing table, dependent on the Hamming distance between the "addresses" of two peers on the network. I'm attempting to ...
5
votes
2answers
106 views
Circular-shift with variable bitlength
For some memory masking operations I need a bitwise-rotation functionality for unsigned integral types. I came across solutions based on the wiki article, but have not found a variation for a function ...
3
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1answer
84 views
K&R Exercise 2-6 : Inserting part of a bitset into another
"Inserting" part of a bitset into another
This is Exercise 2-6 on the K&R book, 2nd edition. The reader is asked to:
Write a function setbits(x,p,n,y) that returns x with the n bits that begin ...
1
vote
1answer
143 views
Adder method of a binary calculator
This is the adder method of my binary calculator. I did not cover for the case that someone passes a non binary number into the calculator yet.
I am pretty sure I have covered every other edge case ...
4
votes
3answers
176 views
Basic binary number container
Summary: a templated class, whose main purpose is to store a binary representation of a decimal number. I choose array of booleans as a storage, since bitset was forbidden. One of the requirements was ...
3
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4answers
140 views
Find the longest length of sequence of 1-bits achievable by flipping a single bit from 0 to 1 in a number
Problem Statement
The problem is defined in the book as following:
5.3 You have an integer and you can flip exactly one bit from 0 to ...
4
votes
2answers
107 views
Checking if a number is a power of 2 without loops
I made a short program which checks if a number is a power of 2 without using any loops.
The idea: A number which is a power of 2 must have only one bit "1" ( ex: 8= 1000, 4=100 and so on).
Suppose ...
2
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0answers
69 views
Kaitai Struct: shift rotate >1 byte groups
This is an implementation of rotation (cyclic shift) of many-byte groups to the left. Rotate right is supported as negative amount. I would like to request, if someone would be willing, to review this ...
4
votes
1answer
63 views
Check digital input signals that is sent as an integer using bitwise checking
I have a program that works with a hardware via an ActiveX API. The API have events that is triggered by the hardware.
In the hardware there is an IO card. There is 16 in and 16 out. Changes in input ...
6
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2answers
574 views
Bitwise comparison of any structure
What I tried to do is compare arbitrary structures independent of the == operator implementation.
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5
votes
1answer
107 views
C++ container — variable byte coded numbers list
I'm writing a container for unsigned integers, which uses variable byte coding. It works but some decisions I took look ugly so I would be glad if you gave me some hints for improving the design.
I ...
4
votes
4answers
355 views
Calculating linux based octal file permission
I'm applying for a mid level devloper position.
In order to progress to 2nd interview, you need to pass a technical test.
One of the questions was to write a function to work out linux based octal ...
2
votes
1answer
157 views
Reading/writing single bits from/to FILE
I'm implementing a Huffman encoding/decoding program and I need a way to deal with single bits.
I tried to keep things as simple as possible, I "pack" bits inside a single byte and I have only one ...
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2answers
2k views
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1answer
370 views
Bitfield class and Register depiction
For a few months now I have been working with an ARM CPU. To be specific an ARM Cortex M3 from STM (STM32107VC). Complete example
So far I am using the StdPeriphal library, and will continue to do so ...
4
votes
1answer
52 views
An application that compares two lists of byte strings
I am a beginner in Rust, and I am trying to write a program that compares common bits between two lists of bits. The program below does that (with the variable names indicating the domain of ...
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votes
2answers
134 views
Map a range of integers to a 64-bit integer
Given a 64-bit integer x (which is always larger than 0), we wish to map it to an index so that:
when x is between 0..64, we map it to 0,
when x is between 65..128,...
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2answers
58 views
The program that reverses bytes in two distinct ways (in C++)
Will be grateful if anyone would reasonably comment on my code. I am interested in the style only. If there will be any comments which are not related to the style I am glad to read them as well.
<...
2
votes
2answers
249 views
Hamming distance
I am wondering how I can improve the runtime of this code. I was solving this task at leetcode, and came up with this solution. But I got the result that my runtime is 88 ms, which beats a bit more ...
3
votes
1answer
475 views
Finding binary gap in Java
I want to know the performance of my code for following problem description.
For example, number 9 has binary representation 1001 and contains a binary gap of length 2. The number 529 has binary ...
3
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3answers
750 views
5
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5answers
316 views
Rotating 3D bit board in C
I've got a 64 bit bitboard, but instead of interpreting as an 8 by 8 binary matrix, as is usually the case, I've taken it to the third dimension, so to speak.
Now mirroring and even rotating by 180 ...
6
votes
2answers
432 views
Variable integer encoding
There is a varint encoding, which I call LEP64 (Little Endian Prefix Max 64-bit).
Basically, the first byte of the encoded value tells us, how many bytes follow (needed bytes encoded in unary coding, ...
6
votes
1answer
422 views
Creating and storing binary arrays
I recently created a library in C, which creates and stores binary arrays. My library uses the standard fixed data types and allocates no more than 8 bytes for a binary array (8 bytes = 64-bit ...
6
votes
1answer
100 views
Take first 12 bits of a number if longer than 12
I need to only take first 12 bits of a number if its longer than a 12 bit number and convert it to a decimal number. So if 7000 is entered than it will return 3500. I also print out the binary form of ...
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1answer
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Sending data from UART to microcontroller via AT89C2051 functioning as a UART/SPI bridge
I have an unusual setup. I have an AT89S52 microcontroller in which its UART is used by the PC. I needed a way to make a second UART based device work with it, so what I decided to do was make a UART ...
2
votes
0answers
168 views
Binary addition in VB.net
It starts by taking two user input from the console and putting them into strings. I then pad them to get them to the same length. I get the length of the num1 and assign it to the integer len. I then ...
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3answers
310 views
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2answers
536 views
Space and time efficient Algorithm for generating prime numbers
I have developed an algorithm for generating prime numbers (which turns out to be an optimized version of the Sieve of Eratosthenes) by reducing the space by a factor of 64.
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6
votes
3answers
84 views
Minimal stack from unsigned int to track boolean values wtih bits
This grew out of a need to track sequential ctrl+shift+Left/Right-arrow keypress events on a gtk editor. It is a small stack implementation for boolean values (for <...
3
votes
1answer
87 views
Gradient noise class based on Simplex noise
Here's a seedable 2D and 3D gradient noise class in C# that I wrote based on Simplex noise. Seems to work properly (even though it's highly experimental). I'm looking for tips to improve the quality ...
6
votes
1answer
231 views
YouTube playlist steganography: hide secret messages inside YouTube playlists
I have created this repo on GitHub and I have shown how this software works through a video.
If you have time, please visit the repo and read the files. I'll post some relevant snippets below, but if ...
6
votes
2answers
363 views
Shifting an 128-bit integer consisting of four 32-bit integers
For a little project of mine I have written two versions for shifting a 128-bit unsigned integer consisting of four 32-bit unsigned integers in x86 assembly. I cannot really decide which is better in ...
5
votes
2answers
289 views
Thread-safe BitArray
Notes:
supports 64-bit platforms only
ulong used where negative values make no sense
library functions are assumed to be correct (whether they actually do what I ...
1
vote
2answers
244 views
Musical graph algorithm, with an inlined lookup helper function
I am working with bit strings in clojure. My question is less about performance and more about how one should go about it (in particular see the last inlined version)
The tonnetz-array represents an ...
15
votes
1answer
3k views
Compressing a 'char' array using bit packing
I have a large array (around 1 MB) of type unsigned char (i.e. uint8_t). I know that the bytes in it can have only one of 5 ...
