# init(bitPattern:) Creates a `UInt256` with the same bit pattern as a signed [`Int256`](/documentation/P256K/Int256) value. ``` init(bitPattern source: Int256) ``` ## Parameters `source` The signed value whose bits are reinterpreted. ## Discussion Preserves the raw 256 bits verbatim; negative `Int256` values become large unsigned values via two’s-complement interpretation. Matches the Swift standard-library convention (e.g. `UInt64(bitPattern: Int64)`).