Re: define pg_structiszero(addr, s, r)

Em qui., 14 de nov. de 2024 às 08:58, Bertrand Drouvot <
bertranddrouvot(dot)pg(at)gmail(dot)com> escreveu:

> Hi,
>
> On Thu, Nov 14, 2024 at 08:22:23AM -0300, Ranier Vilela wrote:
> > Em qui., 14 de nov. de 2024 ąs 07:09, Bertrand Drouvot <
> > bertranddrouvot(dot)pg(at)gmail(dot)com> escreveu:
> >
> > > Hi,
> > >
> > > On Thu, Nov 14, 2024 at 09:27:06AM +0900, Michael Paquier wrote:
> > > > Makes sense to me to just do that, with a first < 8 loop, and a
> second
> > > > for the 8~63 range.
> > >
> > > Thanks for looking at it!
> > >
> > > > There is also a "cant'" in the last size_t check. Simple typo.
> > >
> > > Please find attached v12, with more comments and comments changes to
> > > explain
> > > the multiple cases (for safety) and phases (for efficiency).
> > >
> > Is it worth mentioning that pg_memory_is_all_zeros does not work
> correctly
> > on 32-bit systems?
> >
> > (63 < (size_t) * 8) /* 63 - 32*/
>
> I think that the code is fully portable on 32-bit systems as it's using
> size_t
> in all the places.
>
Maybe I'm doing something wrong.
But I'm testing in 32-bit, with the size set to 63, with v12 and I'm seeing
the SIMD loop execute.
Because the test
if (len < sizeof(size_t) * 8) // 8-63 bytes
failed.

I expected that with size 63, it would be solved by case 2, or am I wrong?

best regards,
Ranier Vilela

PS. Windows 11 64 bits
msvc 32 bits 2022