Bitwise Right Shift (>>) Expression

Summary

Perform a sign-propagating right shift by the specified amount.

Syntax

expression >> amount

Parameters

expression: Any valid numeric expression.
amount: The amount to shift the bits. The amount can be any valid expression.

Description

The >> operator computes the value of the expression on the right, and then shifts the bits of the expression on the left by the specified amount. In a bitwise sign-propagating right shift operation, the value to shift is converted to its binary representation. For example, the decimal (base 10) number 0 (zero) may be converted to the binary form 0000 and the number 1 (one) may be converted to 0001. The bitwise sign-propagating right shift operation will move each bit to the right by the specified amount. For example, if we shift the base 10 number 4 (four) to the right by 2 (two), the operation looks like:

0100 (4)
--------
0001 (1) // 4 >> 2

In this case, the base 10 number 1 (one) is produced by shifting the base 10 number 4 (four) to the right by two.

Copies of the leftmost bit are added to the left, and excess bits on the right that were shifted off are discarded.

Since the leftmost bit (the sign bit) is copied and added to the left, the sign is preserved. Thus, this operation is known as "sign-propagating". As an example, consider a sign-propagating right shift on the value -9 by 2:

11111111111111111111111111110111 (-9)
----------------------------------------------------------------
11111111111111111111111111111101 (-3) // -9 >> 2

Differences from JavaScript

Bitwise right shift operations are not limited to 32-bit integers in JS++. ^{Unimplemented} In JavaScript, the bitwise right shift operation is limited to signed 32-bit integers.

Examples

Basic Usage

import System;
 
Console.log(8 >> 2); // 2

Division by 2 using Bitwise Right Shifts

import System;
 
Console.log(8 >> 1);  // 4
Console.log(4 >> 1);  // 2

External Links

Arithmetic shift [Wikipedia]

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