Example: Bitwise operators in expressions

Symbol (Function)

Description

& (Bitwise AND)

Returns an integer with a bit set to 1 if both of the corresponding bits in the original numbers are 1. Otherwise, the resulting bit is 0.

| (Bitwise inclusive OR)

Returns an integer with a bit set to 1 if either or both of the corresponding bits in the original numbers are 1. If both bits are 0, the resulting bit is 0.

^ (Bitwise exclusive XOR)

Returns an integer with a bit set to 1 if either of the corresponding bits in the original numbers is 1. If both bits are 1 or both are 0, the resulting bit is 0.

>> (Right Shift)

Shifts the bits within the left operand by the amount specified in the right operand. The bit on the right disappears.

Either a 0 or a 1 is shifted in on the left depending on whether the integer is signed or unsigned. With unsigned integers, 0 is always shifted in on the left. With signed integers, a 0 is shifted in when the number is positive (that is, the leftmost bit--the sign bit--is 0), and a 1 is shifted in when the number is negative (that is, the leftmost bit--the sign bit--is 1). In other words, with signed integers, the sign of the number is always maintained.

<< (Left Shift)

Shifts the bits within the left operand by the amount specified in the right operand. The bit on the left disappears and a 0 is shifted in on the right.

If the left bit is a 1, an overflow occurs, and an error message appears. To prevent this, use the bitwise AND (&&) operator in an expression.

For example,

(dev << 1) && 65535, where 65535 is 1111 1111 1111 1111 in binary form.

Where dev is a tag name whose value is being shifted left.

~ (Complement)

Gives the ones complement of a number.

For example, use this operator to reverse every bit within the number so that every 1 bit becomes a 0 and vice versa.