Bitwise Operators in JAVA

transcript

Miscellaneous Lecture by Ali Asghar Manjotho

Lecturer, Department of Computer Systems Engineering, MUET-Jamshoro.

Contents

Bitwise Operators

Bitwise Logical Operators

AND ( & )

OR ( | )

XOR ( ^ )

NOT ( ~ )

Bitwise Shift Operators

Shift Left ( << )

Shift Right Zero Fill ( >>> )

Shit Right ( >> ) 2

Bitwise Operators

Bitwise operators, unlike the other operators, act up on individual bits of their operands.

Can be performed on Boolean and Integer data types as: byte, char, short, int and long.

Bitwise Logical Operators

They perform logical operation on the corresponding bits of the two operands.

Following are the bitwise logical operators:

AND (&)

OR ( | )

NOT ( ~ )

XOR ( ^ ) 5

AND ( & )

It performs logical AND operation on each of the corresponding bits of the two operands as shown below:

A B A & B

AND ( & ) : Example 01

A 0 0 0 0 1 1 0 0 +12

B 0 0 0 0 0 1 0 1 +5

C = A & B 0 0 0 0 0 1 0 0 +4

A = +12 = 00001100

B = +5 = 00000101

A 0 0 0 1 1 1 0 0 +28

B 0 0 1 1 0 0 1 0 +50

C = A & B 0 0 0 1 0 0 0 0 +16

A = +28 = 00011100

B = +50 = 00110010

A 1 1 1 1 0 1 1 0 -10

B 1 1 1 1 1 0 1 1 -5

C = A & B 1 1 1 1 0 0 1 0 -14

For A+10 = 0001010

1110101 1’s Complement+1

-10 = 1110110 2’s Complement-10 = 11110110

For B+5 = 0000101

-5 = 1111011 2’s Complement-5 = 11111011

For C11110010 (Sign + Magnitude)

1110010 (Magnitude)0001101 1’s Complement

+10001110 2’s Complement

0001110 = 14

(C = -14)

OR ( | )

It performs logical OR operation on each of the corresponding bits of the two operands as shown below:

A B A | B

OR ( | ) : Example 01

A 0 0 0 0 1 1 0 0 +12

B 0 0 0 0 0 1 0 1 +5

C = A | B 0 0 0 0 1 1 0 1 +13

A = +12 = 00001100

B = +5 = 00000101

A 0 0 0 1 1 1 0 0 +28

B 0 0 1 1 0 0 1 0 +50

C = A | B 0 0 1 1 1 1 1 0 +62

A = +28 = 00011100

B = +50 = 00110010

A 1 1 1 1 0 1 1 0 -10

B 1 1 1 1 1 0 1 1 -5

C = A | B 1 1 1 1 1 1 1 1 -1

For A+10 = 0001010

-10 = 1110110 2’s Complement-10 = 11110110

For B+5 = 0000101

-5 = 1111011 2’s Complement-5 = 11111011

1111111 (Magnitude)0000000 1’s Complement

0000001 = 1

(C = -1)

XOR ( ^ )

It performs logical XOR operation on each of the corresponding bits of the two operands as shown below:

A B A ^ B

XOR ( ^ ) : Example 01

A 0 0 0 0 1 1 0 0 +12

B 0 0 0 0 0 1 0 1 +5

C = A ^ B 0 0 0 0 1 0 0 1 +9

A = +12 = 00001100

B = +5 = 00000101

A 0 0 0 1 1 1 0 0 +28

B 0 0 1 1 0 0 1 0 +50

C = A ^ B 0 0 1 0 1 1 1 0 +46

A = +28 = 00011100

B = +50 = 00110010

A 1 1 1 1 0 1 1 0 -10

B 1 1 1 1 1 0 1 1 -5

C = A ^ B 0 0 0 0 1 1 0 1 +13

For A+10 = 0001010

-10 = 1110110 2’s Complement-10 = 11110110

For B+5 = 0000101

-5 = 1111011 2’s Complement-5 = 11111011

0001101 (Magnitude)

0001101 = 13

(C = +13)

NOT ( ~ )

It performs logical NOT operation on each of the bit of its operand as shown below:

It inverts the bits (Converts all 1s in to 0s and all 0s in to 1s).

NOT ( ~ ) : Example 01

A 0 0 0 0 1 1 0 0 +12

B = ~A 1 1 1 1 0 0 1 1 -13

A = +12 = 00001100

For B11110011 (Sign + Magnitude)1110011 (Magnitude)0001100 1’s Complement

0001101 = 13

(C = -13) 29

A 0 0 0 1 1 1 0 0 +28

B = ~A 1 1 1 0 0 0 1 1 -29

A = +28 = 00011100

0011101 = 29

(C = -29) 31

A 1 1 1 1 0 1 1 0 -10

B = ~A 0 0 0 0 1 0 0 1 +9

For A+10 = 0001010

-10 = 1110110 2’s Complement-10 = 11110110

For B00001001 (Sign + Magnitude)0001001 (Magnitude)

0001001 = 9

(C = +9)

Bitwise Shift Operators

They shift the corresponding bits of the operand left or right.

First operand is the number to be shifted.

Second operand tells the number of bits to shift.

Following are the bitwise shift operators:

Shift Left (<<)

Shift Right ( >> ) 35

Shift Left ( << )

It shifts the bits of first operand to left.

The second operand tells the number of bits to be shifted.

After performing shift left operation, the empty bits left at the right side will always be filled with 0s.

The result of shifting one bit to left will result multiplication by 2.

Shift Left ( << ) : Example 01

A 0 0 0 0 1 1 0 0 +12

0 0 1 1 0 0 Shifting left 2 bits

0 0 1 1 0 0 0 0 Fill empty bits with 0s

B = A<<2 0 0 1 1 0 0 0 0 +48

A = +12 = 00001100

A 0 0 0 1 0 1 1 0 +22

1 0 1 1 0 Shifting left 3 bits

B = A<<3 1 0 1 1 0 0 0 0 -80

A = +22 = 00010110

For B:101100000110000 (Magnitude)1001111 1’s Complement

+1 2’s Complement1010000

1010000 = 80(B = -80)

A 1 1 1 1 0 1 1 0 -10

1 1 0 1 1 0 Shifting left 2 bits

B = A<<2 1 1 0 1 1 0 0 0 -40

For A+10 = 0001010

-10 = 1110110 2’s Complement-10 = 11110110

0101000 = 40

(B = -40)

It shifts the bits of first operand to right.

After performing shift right zero fill operation, the empty bits left at the left side will always be filled with 0s.

It does not take care about the sign of the number. 43

Shift Right Zero Fill ( >>> ) : Example 01

A 0 0 0 0 1 1 0 0 +12

0 0 0 0 1 1 Shifting right 2 bits

B = A>>>2 0 0 0 0 0 0 1 1 +3

A = +12 = 00001100

For B:00000011 = +3

Shift Right Zero Fill ( >>> ) : Example 02

A 0 0 0 1 0 1 1 0 +22

0 0 0 1 0 Shifting right 3 bits

B = A>>>3 0 0 0 0 0 0 1 0 +2

A = +22 = 00010110

For B:00000010 = +2

(B = +2)

Shift Right ( >> )

It shifts the bits of first operand to right.

After performing shift right operation, the empty bits left at the left side will be filled according to the sign bit of the number.

If sign bit is 0 all the empty bits will be filled with 0s.

If sign bit is 1 all the empty bits will be filled with 1s.

It does care about the sign of the number.

The result of shifting one bit to right will result division by 2. 48

Shift Right ( >> ) : Example 01

A 0 0 1 1 1 1 0 0 +60

0 0 1 1 1 Shifting right 3 bits

0 0 0 0 0 1 1 1 Fill empty bits with sign bit

B = A>>3 0 0 0 0 0 1 1 1 +7

A = +60 = 00111100

For B:00000111 = +7

Shift Right ( >> ) : Example 02

A 1 1 1 1 0 1 1 0 -10

1 1 1 1 0 1 Shifting right 2 bits

1 1 1 1 1 1 0 1 Fill empty bits with sign bit

B = A>>2 1 1 1 1 1 1 0 1 -3

For A:+10 = 0001010

1110110 2’s Complement-10 = 11110110

For B:111111011111101 (Magnitude)0000010 1’s Complement

0000011 = 3

(B = -3)