Re: [PATCH 1/6] rust: num: add `shr` and `shl` methods to `Bounded`

[Alice Ryhl]

On Tue, Jan 20, 2026 at 03:17:54PM +0900, Alexandre Courbot wrote:
> Shifting a `Bounded` left or right changes the number of bits required
> to represent the value. Add methods that perform the shift and return a
> `Bounded` with the appropriately adjusted bit width.
> 
> These methods are particularly useful for bitfield extraction.
> 
> Suggested-by: Alice Ryhl <aliceryhl@xxxxxxxxxx>
> Signed-off-by: Alexandre Courbot <acourbot@xxxxxxxxxx>

Reviewed-by: Alice Ryhl <aliceryhl@xxxxxxxxxx>

> +    /// Right-shifts `self` by `SHIFT` and returns the result as a `Bounded<_, { N - SHIFT }>`.
> +    ///
> +    /// # Examples
> +    ///
> +    /// ```
> +    /// use kernel::num::Bounded;
> +    ///
> +    /// let v = Bounded::<u32, 16>::new::<0xff00>();
> +    /// let v_shifted: Bounded::<u32, 8> = v.shr::<8, _>();
> +    ///
> +    /// assert_eq!(v_shifted.get(), 0xff);
> +    /// ```
> +    pub fn shr<const SHIFT: u32, const RES: u32>(self) -> Bounded<T, RES> {
> +        const { assert!(RES == N - SHIFT) }

In principle this could be

const { assert!(RES >= N - SHIFT) }

Alice