Flash CS3 Documentation

ActionScript 2.0 Language Reference > ActionScript language elements > Operators > >> bitwise right shift operator

>> bitwise right shift operator

expression1 >> expression2

Converts expression1 and expression2 to 32-bit integers, and shifts all the bits in expression1 to the right by the number of places specified by the integer that results from the conversion of expression2 . Bits that are shifted off the right end are discarded. To preserve the sign of the original expression , the bits on the left are filled in with 0 if the most significant bit (the bit farthest to the left) of expression1 is 0, and filled in with 1 if the most significant bit is 1. Shifting a value right by one position is the equivalent of dividing by 2 and discarding the remainder.

Floating-point numbers are converted to integers by discarding any digits after the decimal point. Positive integers are converted to an unsigned hexadecimal value with a maximum value of 4294967295 or 0xFFFFFFFF; values larger than the maximum have their most significant digits discarded when they are converted so the value is still 32-bit. Negative numbers are converted to an unsigned hexadecimal value via the two's complement notation, with the minimum being -2147483648 or 0x800000000; numbers less than the minimum are converted to two's complement with greater precision and also have the most significant digits discarded.

The return value is interpreted as a two's complement number with sign, so the return value will be an integer in the range -2147483648 to 2147483647.

Availability: ActionScript 1.0; Flash Player 5

Operands

expression1 : Number - A number or expression to be shifted right.

expression2 : Number - A number or expression that converts to an integer from 0 to 31.

Returns

Number - The result of the bitwise operation.

Example

The following example converts 65535 to a 32-bit integer and shifts it 8 bits to the right:

var x:Number = 65535 >> 8; 
trace(x); // outputs 255

The following example shows the result of the previous example:

var x:Number = 255;

This is because 65535 decimal equals 1111111111111111 binary (sixteen 1s), 1111111111111111 binary shifted right by 8 bits is 11111111 binary, and 11111111 binary is 255 decimal. The most significant bit is 0 because the integers are 32-bit, so the fill bit is 0.

The following example converts -1 to a 32-bit integer and shifts it 1 bit to the right:

var x:Number = -1 >> 1;
trace(x); // outputs -1

The following example shows the result of the previous example:

var x:Number = -1;

This is because -1 decimal equals 11111111111111111111111111111111 binary (thirty-two 1s), shifting right by one bit causes the least significant (bit farthest to the right) to be discarded and the most significant bit to be filled in with 1. The result is 11111111111111111111111111111111 (thirty-two 1s) binary, which represents the 32-bit integer -1.

See also

>>= bitwise right shift and assignment operator

Flash CS3