<!--
{
  "availability" : [
    "iOS: 18.0.0 -",
    "iPadOS: 18.0.0 -",
    "macCatalyst: 18.0.0 -",
    "macOS: 15.0.0 -",
    "tvOS: 18.0.0 -",
    "visionOS: 2.0.0 -",
    "watchOS: 11.0.0 -"
  ],
  "documentType" : "symbol",
  "framework" : "Swift",
  "identifier" : "/documentation/Swift/Int128/&=(_:_:)",
  "metadataVersion" : "0.1.0",
  "role" : "Operator",
  "symbol" : {
    "kind" : "Operator",
    "modules" : [
      "Swift"
    ],
    "preciseIdentifier" : "s:s6Int128V2aeoiyyABz_ABtFZ"
  },
  "title" : "&=(_:_:)"
}
-->

# &=(_:_:)

Stores the result of performing a bitwise AND operation on the two given
values in the left-hand-side variable.

```
static func &= (a: inout Int128, b: Int128)
```

## Discussion

A bitwise AND operation results in a value that has each bit set to `1`
where *both* of its arguments have that bit set to `1`. For example:

```
var x: UInt8 = 5          // 0b00000101
let y: UInt8 = 14         // 0b00001110
x &= y                    // 0b00000100
```

---

Copyright &copy; 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)