# 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.

294 questions
Filter by
Sorted by
Tagged with
328 views

### How to optimize bitwise get/set/clear of ranges of bits in JavaScript?

I have been working for a few days on writing get, set, and clear bitwise functions in ...
46 views

### Array-like data structure for fixed sized types with non-machine-word sizes

I am writing an array-like data structure for types other than 8 16 32 64 – the usual type sizes. Ideally, my interface is the following for addressing the array. ...
220 views

### Parsing a sequence of bits out of a bit field

For homework, I had to parse CPUID instruction output in C, which required a lot of specific bit-manipulation like: (eax & CACHE_LEVEL) >> 5 I ...
28 views

### Implementing a Hilbert-like space-filling-curve conversion in Rcpp

I have written a series of functions that are designed to create a space-filling curve (similar to a Hilbert Curve) that is intended for symmetric matrices (as opposed to a square region). I plan to ...
64 views

### Factoring the powers of 2 in Python

The powers of 2 are trivial to factor because all powers of 2 have one 1-bit and the rest 0-bits. Just iterate minus one 0-bit as follows: 10000,1000,100,10,1. And then convert the binary strings into ...
6k views

### Decide if the sum of three numbers is even or odd

Exercise from an Assembly course I'm enrolled into: Write a program that takes three numbers x,y,z as input, and returns: 0 if (x+y+z) is even. 1 if (x+y+z) is odd. (Note that ...
67 views

### Von Neumann random bytes debiasing

I need to create a method to debias biased bytes from the method get_raw_bytes(length) using von Neumann debiasing method. Von ...
140 views

### Routine to convert decimal digits to Densely Packed Decimal

I've written an amd64 assembly routine (in gas syntax using the System V calling convention) to convert three decimal digits to Densely packed decimal because I wasn't satisfied by the performance of ...
158 views

### Find out whether number is of Power of Two

The task is taken from leetcode Given an integer, write a function to determine if it is a power of two. Example 1: Input: 1 Output: true Explanation: 20 = 1 Example 2: ...
62 views

### ROT128 byte-transformation encoding

I'd like some feedback on code I wrote to obfuscate text on-disk. The basic idea is the same as ROT13 (which is implemented in the Python standard library), except instead of rotating the English ...
78 views

### LeetCode: Sum of Two Integers C#

https://leetcode.com/problems/sum-of-two-integers/ Calculate the sum of two integers a and b, but you are not allowed to use the operator + and -. Example 1: Input: a = 1, b = 2 Output: ...
13k views

### Counting the number of bits of a positive integer

How can I improve this code for counting the number of bits of a positive integer n in Python? ...
82 views

### Fun crypto problem: Exploiting a vulnerable encryption scheme with Python

I came across a question asked here and here on the Crypto Stack Exchange site, and decided to analyze it as a kind of case study. To demonstrate the concept, I wrote a short python script depicting ...
136 views

### Bit shift 256 bits

I have a working solution to my problem, but I'm less than satisfied with the result, both when it comes to style and performance. In short, I need to be able to shift 256 bits of data, say an array ...
62 views

### Swapping Nibbles

I have small (<250 bytes) chunk of binary data, where I know that almost always, the first nibble is going to be zero 0. For example, in hex: ...
2k views

2k views

### Codility binary gap solution

This is how I solved the binary gap problem: Find longest sequence of zeros, bounded by ones, in binary representation of an integer I wonder how does it fare against solutions such as ones appeared ...
111 views

### Bitmap in Bitmap (Black & white)

Below is my attempt at bitmap in bitmap searching using 1bpp bitmaps. Any suggestions on how I can reduce complexity and improve speed? Any comment is appreciated. ...
19k views

### Find the binary gap of a number N

For example, number 9 has binary representation 1001 and contains a binary gap of length 2. The number 529 has binary representation 1000010001 and contains two binary gaps: one of length 4 and one of ...
4k views

### Codility binary gap solution using regex

Below is the code I implemented to solve the binary gap problem: Find longest sequence of zeros, bounded by ones, in binary representation of an integer. However, it seems to be different from ...
68 views

### converting bits binary to bcd

I wrote a code that requests user input and then converts binary to bcd then back to binary using bitwise operations. While I think my code is good I want to know if there is a better way to write the ...
31 views

### Basic Subnet Mask Calculator + A Little Extra

For my Networking class, we learned about subnetting and subnet masks. I decided to write a little "calculator" (a generous term) that when given n-many network ...
173 views

### Adding two n and m bit binary numbers

Recently I was studying bitwise operators and bit-manipulation algorithms and I found out an algorithm to add two binary numbers. Pseudocode is as follows: ...
79 views

### Interlock of some equipments in electrical power system using simple Arduino Uno code [closed]

I'm trying to implement some logic functions essential to control a small power system consisting of 2 Transformers labeled T1 and T2, 2 Generators (G1 and G2) and a bus tie (BT). I'm not going to ...
2k views

### Steganography for images

For a school project I'm working on a small library to do steganography. I've just finished the first method of steganography and thought I'd get some feedback. This steganography method works by ...
158 views

### Assembler-program which reverses the content of EAX

Following exercise: Write a program that takes a number (of size 4 bytes) x as input, and then reverses all the bits of x, and outputs the result. By reversing all bits we mean that the ...
416 views

### Proper Case Conversion (Performance)

I wrote a simple function that converts an array of words into proper case (using bitwise operations) and returns the array. I performed a simple test using ...
280 views

### “Fast strlen” in C using scalar bithacks

I've translated an implementation of strlen in x86 assembly to C and added alignment checking: ...
291 views

### Decoding of binary data (AIS) from socket

I am currently working on a AIS message decoder written in pure Python. It's just a little project to teach me some things about binary data, decoding, etc. Because I am only programming for about a ...
113 views

### Byte extension methods for common bitwise operations

I'd like to learn how I can optimize the following byte extension methods. I'm targeting .NET Standard 2.0 but I'm curious if there are any ways to go about some of this functionality using features ...
9k views

### Calculating the 'binary gap' of a number

Inspired by this question and therefore this one I decided that clearly the best most readable way to solve this is with Regular Expressions. A binary gap within a positive integer N is any maximal ...
128 views

### A bitwise common prefix algorithm in Python

Is my algorithm slow because it has problems? Or, is any bitwise common prefix solution not going to give me the performance I'm looking for? After profiling my algorithm, I found that over 60% of ...
910 views

### overload c++ enum class operators and enable check value set

I use c++ 11 enum class usually instead of the old enums because many enums can contain the same value but as known they don't have the bitwise operators out of the box so we should define them ...
35 views

### Invert bits of a number in clojurescript

Doing a challenge to print the number that you would get if you convert a given number to binary, invert its bits, then convert back to decimal. I decided to give it a run in clojurescript (which I ...
90 views

### Invert bits of binary representation of number

This is the code I came up with. I added comments to make the solution more verbose. ...
45 views

### LeetCode Count number of set bits solution

Question - Write a function that takes an unsigned integer and return the number of '1' bits it has (also known as the Hamming weight). ...
1k views

### Bouncing map back into its bounds, after user dragged it out

Users like exploring maps, seeing all that is around. However they tend to go too far. To prevent the map from getting lost to the user it bounces back into the set bounds, as defined by a rectangle. ...
81 views

### Binary Trie in F#

I have this little exercise writing a binary trie in F#. In C# it can be done in few lines, but here it became more complicated than I had expected (especially the ...
83 views

### Count all X-shaped bits from 8 integers

I am given 8 positive 32-bit integer numbers. The task is to write program to count all X-bits. X-bits are groups of 9 bits (3 rows x 3 columns) forming the letter "X". task is to count all X-bits ...
69 views

### Set a specific bit to a specific value [closed]

This is the code I came up with: ...
398 views

### pythonic way to split bytes

I have incoming data from an absolute rotary encoder. It is 24 bits wide. 12 bits are the number of turns and 12 bits are the angle. I'm reading the data with an Arduino and sending it to the ...
379 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 ...
78 views

### Go command-line tool to do some simple byte manipulation

I have some files containing 16-bit words in big-endian order, and a tool to process them that assumes little-endian order. I therefore need to swap the order of each pair of bytes in my files. This ...
78 views

### Indeterminate-length big-endian to little-endian conversion in Python

I have a need to convert wire encoding (big-endian) to little-endian in Python. The conversion needs to happen as a separate function; I am not allowed to change the function that reads the byte ...
126 views

### Templated division by a power of 2

I've implemented a div_by_power_of_2() function, which lets me force the compiler to use left-shifting rather than proper division, in cases when the developer know ...
302 views

### Register “%b” conversion specifier

I'm writing a library to register the b, B conversion specifiers and make them work the closest possible to ...
906 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 ...
159 views

### Java code to convert BigDecimal to/from .NET decimal

Background In many languages we have built-in data types for representing decimal floating point numbers. In .NET that's decimal, and in Java we have ...