Re: agp_nvidia port for review

[Valery Ushakov <uwe%stderr.spb.ru@localhost>]

On Tue, Jun 09, 2026 at 01:29:10 +0300, Andrius V wrote:

> > > > Why the intermediate val, and the cast?  Why not just:
> > > >
> > > >         switch (pci_conf_read(sc->as_pc, sc->as_tag, AGP_NVIDIA_0_APSIZE) &
> > > >             0xff) {
> > > >
> > >
> > > I think I felt that it was a very "bulky" statement for a switch key.
> >
> > I'd agree.  A better variable name than "val" would also help.  For a
> > drive-by reader it's also not so clear what does 0xff do.  Is it an
> > expected part of obtaining the `apsize` value, or does does it select
> > a subfield, or something...  In the one-liner - "APSIZE" is hidden in
> > the middle of a long line, closer to the rigtht marging, and further
> > obscured by the all-caps prefix before it and the bitmask after it.
> > `switch (apsize)` OTOH, is easier to read.
>
> Renamed variable to reg and used pcireg_t type to make consistent with
> agp_nvidia_set_aperture() variable name.
> The mask was supposed to be 0x0f to take the lower four bits of the
> aperture size field. Fixed that...

Thats's a _horrible_ name :)

Looking at agp_nvidia_set_aperture I guess the right name for this
variable is "key", if only for consistency with the inverse function.

prcireg_t is what you "physically" read (or write, in the setter), but
the "key" you are extracting from it and looking at here is something
else.

-uwe