In computer programming

Computer programming

Computer programming is the process of designing, writing, testing, debugging, and maintaining the source code of computer programs. This source code is written in one or more programming languages. The purpose of programming is to create a program that performs specific operations or exhibits a...

, an arithmetic shift is a shift operator

Shift operator

In mathematics, and in particular functional analysis, the shift operator or translation operator is an operator that takes a function to its translation . In time series analysis, the shift operator is called the lag operator....

, sometimes known as a signed shift (though it is not restricted to signed operands). For binary number

Binary numeral system

The binary numeral system, or base-2 number system, represents numeric values using two symbols, 0 and 1. More specifically, the usual base-2 system is a positional notation with a radix of 2...

s it is a bitwise operation

Bitwise operation

A bitwise operation operates on one or more bit patterns or binary numerals at the level of their individual bits. This is used directly at the digital hardware level as well as in microcode, machine code and certain kinds of high level languages...

 that shifts all of the bits of its operand; every bit in the operand is simply moved a given number of bit positions, and the vacant bit-positions are filled in. Instead of being filled with all 0s, as in logical shift

Logical shift

In computer science, a logical shift is a bitwise operation that shifts all the bits of its operand. Unlike an arithmetic shift, a logical shift does not preserve a number's sign bit or distinguish a number's exponent from its mantissa; every bit in the operand is simply moved a given number of bit...

, when shifting to the right, the leftmost bit (usually the sign bit

Sign bit

In computer science, the sign bit is a bit in a computer numbering format that indicates the sign of a number. In IEEE format, the sign bit is the leftmost bit...

 in signed integer representations) is replicated to fill in all the vacant positions (this is a kind of sign extension

Sign extension

Sign extension is the operation, in computer arithmetic, of increasing the number of bits of a binary number while preserving the number's sign and value...

).

Arithmetic shifts can be useful as efficient ways of performing multiplication or division of signed integers by powers of two.