bitwise


bitwise

(programming)A bitwise operator treats its operands as avector of bits rather than a single number. Booleanbitwise operators combine bit N of each operand using aBoolean function (NOT, AND, OR, XOR) to produce bitN of the result.

For example, a bitwise AND operator ("&" in C) wouldevaluate 13 & 9 as (binary) 1101 & 1001 = 1001 = 9, whereas,the logical AND, (C "&&") would evaluate 13 && 9 as TRUE &&TRUE = TRUE = 1.

In some languages, e.g. Acorn's BASIC V, the same operatorsare used for both bitwise and logical operations. Thisusually works except when applying NOT to a value x which isneither 0 (false) nor -1 (true), in which case both x and (NOTx) will be non-zero and thus treated as TRUE.

Other operations at the bit level, which are not normallydescribed as "bitwise" include shift and rotate.

bitwise

Dealing with bits rather than larger structures such as a byte. For example, each of the eight bits in a byte can be used as an individual flag to signal yes/no, on/off (1 or 0) about some condition. The Boolean operators AND, OR and NOT also deal with individual bits rather than bytes.

Bitwise operators are programming commands that work with individual bits. The primary ones are:

Symbol Function << Shift left 4 bits >> Shift right 4 bits & AND | OR ^ XOR (Exclusive OR) ~ NOT (0 to 1; 1 to 0)