Operator

&>>(_:_:)

Returns the result of shifting a value’s binary representation the specified number of digits to the right, masking the shift amount to the type’s bit width.

Declaration

static func &>> (lhs: Int32, rhs: Int32) -> Int32

Parameters

lhs

The value to shift.

rhs

The number of bits to shift lhs to the right. If rhs is outside the range 0..<lhs.bitWidth, it is masked to produce a value within that range.

Discussion

Use the masking right shift operator (&>>) when you need to perform a shift and are sure that the shift amount is in the range 0..<lhs.bitWidth. Before shifting, the masking right shift operator masks the shift to this range. The shift is performed using this masked value.

The following example defines x as an instance of UInt8, an 8-bit, unsigned integer type. If you use 2 as the right-hand-side value in an operation on x, the shift amount requires no masking.

let x: UInt8 = 30                 // 0b00011110
let y = x &>> 2
// y == 7                         // 0b00000111

However, if you use 8 as the shift amount, the method first masks the shift amount to zero, and then performs the shift, resulting in no change to the original value.

let z = x &>> 8
// z == 30                        // 0b00011110

If the bit width of the shifted integer type is a power of two, masking is performed using a bitmask; otherwise, masking is performed using a modulo operation.