Bitoperations

Bitoperations are operations that manipulate individual bits within data, a fundamental concept in digital logic and low-level programming. They enable compact data representations, efficient flag management, and fast bitwise testing and modification. The core bitwise operators are AND, OR, XOR, and NOT, which operate on corresponding bits of two operands. Bit shifts move bits left or right; logical shifts fill with zeros, while arithmetic right shifts preserve the sign bit for signed integers. Some languages also provide bit rotations.

A common technique is masking, which uses specific bit patterns to set, clear, toggle, or test bits. To set a bit, combine the value with a mask created by shifting 1 left by the bit index. To clear a bit, use the complement of the same mask and apply AND. To toggle, apply XOR with the mask. To test, perform an AND with the mask and check the result.

Additional concepts include population count, which counts how many bits are set in a value, and related bit-scanning operations that locate the position of set bits. These operations may be supported directly by modern CPUs and exposed through language libraries.

Applications span systems programming, graphics, networking, compression, and game development. Bitboards in board games, flags in configuration data, and compact encodings rely on bitoperations for speed and space efficiency.

Portability and correctness considerations include language-specific rules for shifts (such as signed versus unsigned types), behavior when shifting by a value outside the bit width, and endianness affecting memory layout rather than bitwise logic. Clear understanding of the language semantics helps avoid common pitfalls.