Answer 1

A bit field is a data structure used in computer programming. It consists of a number of adjacent computer memory locations which have been allocated to hold a sequence of bits, stored so that any single bit or group of bits within the set can be addressed.[1][2] A bit field is most commonly used to represent integral types of known, fixed bit-width.

The meaning of the individual bits within the field is determined by the programmer; for example, the first bit in a bit field (located at the field's base address) is sometimes used to determine the state of a particular attribute associated with the bit field.[3]

Within microprocessors and other logic devices, collections of bit fields called "flags" are commonly used to control or to indicate the intermediate state or outcome of particular operations.[4] Microprocessors typically have a status register that is composed of such flags, used to indicate various post-operation conditions, for example an arithmetic overflow. The flags can be read and used to decide subsequent operations, such as in processing conditional jump instructions. For example, a je (Jump if Equal) instruction in the x86 assembly language will result in a jump if the Z (zero) flag was set by some previous operation.

A bit field is distinguished from a bit array in that the latter is used to store a large set of bits indexed by integers and is often wider than any integral type supported by the language.[5] Bit fields, on the other hand, typically fit within a machine word,[3] and the denotation of bits is independent of their numerical index.[2]