https://github.com/tgymnich/bitwiserotate

🔄 Safe and efficient bitwise rotation in Swift
https://github.com/tgymnich/bitwiserotate

bitwise-operators bitwise-rotation rol ror rotation swift swift-library

Last synced: 4 days ago
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🔄 Safe and efficient bitwise rotation in Swift

• Host: GitHub
• URL: https://github.com/tgymnich/bitwiserotate
• Owner: tgymnich
• License: mit
• Created: 2020-06-09T20:50:35.000Z (about 5 years ago)
• Default Branch: main
• Last Pushed: 2021-12-02T02:47:21.000Z (over 3 years ago)
• Last Synced: 2025-03-31T08:30:38.632Z (3 months ago)
• Topics: bitwise-operators, bitwise-rotation, rol, ror, rotation, swift, swift-library
• Language: Swift
• Homepage:
• Size: 50.8 KB
• Stars: 3
• Watchers: 3
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# BitwiseRotate

![Swift](https://github.com/tgymnich/BitwiseRotate/workflows/Swift/badge.svg)

[![codecov](https://codecov.io/gh/tgymnich/BitwiseRotate/branch/main/graph/badge.svg?token=K3HRG7M134)](https://codecov.io/gh/tgymnich/BitwiseRotate)

A swift package providing bitwise rotation operators for `FixedWidthInteger` and `SIMD` vectors with a `FixedWidthInteger` scalar.

This package is written in a sepcific way to [compile](https://www.godbolt.org/z/4Ggohy) to `ror` and `rol` on x86. On ARM only `UInt32`, `UInt64`, `Int32` and `Int64` [compile](https://gist.github.com/tgymnich/84f1cfed5038dff435c9cdb28ceb8f10) to `ror`. Rotations on `SIMD` vectors don't yet compile to the most efficient instructions possible.

# Setup

In your Package.swift add:

```swift

.package(url: "https://github.com/tgymnich/BitwiseRotate.git", from: "1.1.1")

```

# Usage

## rol

```swift

let someBits: UInt8 = 0b01010100 <<< 3 // returns 0b10100010

```

## ror

```swift

let someBits: UInt8 = 0b01010100 >>> 3 // returns 0b10001010

```

## SIMD

```swift

let someBitVector = SIMD3(arrayLiteral: 0b01010100,0b11011100,0b00011000) <<< 1 // (0b10101000, 0b10111001, 0b00110000) 

```