Re: [PATCH RFC 1/3] rust: add useful ops for u64

[Danilo Krummrich <dakr@kernel.org>]

On Fri, Feb 21, 2025 at 08:35:54PM +0900, Alexandre Courbot wrote:
> On Thu Feb 20, 2025 at 9:14 AM JST, John Hubbard wrote:
> > On 2/19/25 3:13 PM, Daniel Almeida wrote:
> >>> On 19 Feb 2025, at 17:23, Dave Airlie <airlied@gmail.com> wrote:
> >>> On Thu, 20 Feb 2025 at 06:22, John Hubbard <jhubbard@nvidia.com> wrote:
> >>>> On 2/19/25 4:51 AM, Alexandre Courbot wrote:
> >>>>> Yes, that looks like the optimal way to do this actually. It also
> >>>>> doesn't introduce any overhead as the destructuring was doing both
> >>>>> high_half() and low_half() in sequence, so in some cases it might
> >>>>> even be more efficient.
> >>>>>
> >>>>> I'd just like to find a better naming. high() and low() might be enough?
> >>>>> Or are there other suggestions?
> >>>>>
> >>>>
> >>>> Maybe use "32" instead of "half":
> >>>>
> >>>>      .high_32()  / .low_32()
> >>>>      .upper_32() / .lower_32()
> >>>>
> >>>
> >>> The C code currently does upper_32_bits and lower_32_bits, do we want
> >>> to align or diverge here?
> >
> > This sounds like a trick question, so I'm going to go with..."align". haha :)
> >
> >>>
> >>> Dave.
> >> 
> >> 
> >> My humble suggestion here is to use the same nomenclature. `upper_32_bits` and
> >> `lower_32_bits` immediately and succinctly informs the reader of what is going on.
> >> 
> >
> > Yes. I missed the pre-existing naming in C, but since we have it and it's
> > well-named as well, definitely this is the way to go.
> 
> Agreed, I wasn't aware of the C equivalents either, but since they exist
> we should definitely use the same naming scheme.

IIUC, we're still talking about extending the u64 primitive type.

Hence, I think there is no necessity to do align with the corresponding C
nameing scheme. I think this would only be the case if we'd write an abstraction
for the C API.

In this case though we extend an existing Rust type, so we should do something
that aligns with the corresponding Rust type.

In this specific case I think it goes hand in hand though.

- Danilo