The IEEE Standard for Floating-Point Arithmetic (IEEE 754) is a technical standard for floating-point arithmetic originally established in 1985 by the Institute of Electrical and Electronics Engineers (IEEE). The standard addressed many problems found in the diverse floating-point implementations that made them difficult to use reliably and portably. Many hardware floating-point units use the IEEE 754 standard.
The standard defines:
arithmetic formats: sets of binary and decimal floating-point data, which consist of finite numbers (including signed zeros and subnormal numbers), infinities, and special "not a number" values (NaNs)
interchange formats: encodings (bit strings) that may be used to exchange floating-point data in an efficient and compact form
rounding rules: properties to be satisfied when rounding numbers during arithmetic and conversions
operations: arithmetic and other operations (such as trigonometric functions) on arithmetic formats
exception handling: indications of exceptional conditions (such as division by zero, overflow, etc...