Javascript-15-Bitwise operations

Bitwise Operations

Notes: 

• JavaScript uses 32-bit signed numbers.

Bitwise AND : 1&1 = 1, else 0

Bitwise OR: 0|0 = 0, else 1

Bitwise XOR: 1^1 = 1, 0^0 = 1, else 0

Bitwise ~ : 

~5 =>  (bitform of the number+ 1). 

• Another trick is, ~(number) = -(number+1). ie, ~5 = -(6)

Bitwise -(negation)

However, -(5) = retain last digit and swap the rest.

ie, -5 

5 = 00000000000000000000000000000101

-5 = 11111111111111111111111111111011

(Zero Fill) Bitwise Left Shift (<<): 

• 5 << 1 = 10; ie, 
• 00000000000000000000000000000101 
• <<
• 1
• = 
• 00000000000000000000000000001010 (ie, 000..0(2power3)0(2power1)0

(Zero Fill) Right Shift (>>>):

• 5 >>> 1 = 2; ie, 
• 00000000000000000000000000000101 
• >>>
• 1
• = 
• 00000000000000000000000000000010 (ie, 000..0(2power1)0 == 2)

(Sign Preserving) Bitwise Right Shift (>>): 

• -5 >> 1 = -3; ie, 
• 11111111111111111111111111111011
• >>
• 1
• =
• 11111111111111111111111111111101 ---(a)
• here's the trick, 
• shift 1 place in bit format to get (a) and 
• retain last digit after  and 
• swap the rest. Now u get a decimal. 
• add -ve to the obtained decimal.. hence in the above case..
• 00000000000000000000000000000011 .. which is 3. 
• Now add -ve to 3.. hence -3

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Decimal to Binary function:

function dec2bin(dec){
    return (dec >>> 0).toString(2);
}

Binary to Decimal function:

function bin2dec(bin){
    return parseInt(bin, 2).toString(10);
}

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