Bit Shift Operator

Overview

Bit Shift operator will shift right or left by specified bit numbers.

var a = 0x05;
var b = a << 1;   // 0101 << 1 => 1010
var c = b >> 1;   // 1010 >> 1 => 0101

This can be also used with assignment operator as <<= or >>=. Those operators will automatically make it promote to Big Integer when it is over 64 bit integer range.

var a = 0x05;
a <<= 0x06;          // 0101 << 6 => 0101000000

Note that Bit OR operator will treat null as 0.

Examples

Example 1. Shift left

Code

function test(a, b) {
    return a << b;
}

System.println(test(0x05, 1));
System.println(test(10, 11));
System.println(test(null, 0x05));
System.println(test(0x07, null));

Result

10
20480
0
7

Example 2. Shift right

Code

function test(a, b) {
    return a >> b;
}

System.println(test(0x0a, 1));
System.println(test(1024, 4));
System.println(test(null, 0x05));
System.println(test(0x07, null));

Result

5
64
0
7

Example 3. Big Integer Shift left

Code

function test(a, b) {
    return (a << b).toString(16);
}

System.println(test(0x7fffffffffffffff, 2));
System.println(test(0x7fffffffffffffff + 1, 2));

Result

1fffffffffffffffc
20000000000000000

Example 4. Big Integer Shift right

Code

function test(a, b) {
    return (a >> b).toString(16);
}

System.println(test(0x7fffffffffffffff * 2, 2));
System.println(test((0x7fffffffffffffff + 1) * 2, 2));
System.println(test((0x7fffffffffffffff + 1) * 8, 2));

Result

3fffffffffffffff
4000000000000000
10000000000000000