[PATCH v4 1/3] lib/vsprintf: Add support for generic FourCCs by extending %p4cc

[Geert Uytterhoeven]

Hi Andy,

On Tue, 22 Apr 2025 at 12:12, Andy Shevchenko
<andriy.shevchenko at linux.intel.com> wrote:
> On Tue, Apr 22, 2025 at 10:07:33AM +0200, Geert Uytterhoeven wrote:
> > On Tue, 8 Apr 2025 at 08:48, Aditya Garg <gargaditya08 at live.com> wrote:
>
> ...
>
> > > +Generic FourCC code
> > > +-------------------
> > > +
> > > +::
> > > +       %p4c[hnlb]      gP00 (0x67503030)
> > > +
> > > +Print a generic FourCC code, as both ASCII characters and its numerical
> > > +value as hexadecimal.
> > > +
> > > +The generic FourCC code is always printed in the big-endian format,
> > > +the most significant byte first. This is the opposite of V4L/DRM FourCCs.
> > > +
> > > +The additional ``h``, ``n``, ``l``, and ``b`` specifiers define what
> > > +endianness is used to load the stored bytes. The data might be interpreted
> > > +using the host byte order, network byte order, little-endian, or big-endian.
> > > +
> > > +Passed by reference.
> > > +
> > > +Examples for a little-endian machine, given &(u32)0x67503030::
> > > +
> > > +       %p4ch   gP00 (0x67503030)
> > > +       %p4cn   00Pg (0x30305067)
> > > +       %p4cl   gP00 (0x67503030)
> > > +       %p4cb   00Pg (0x30305067)
> > > +
> > > +Examples for a big-endian machine, given &(u32)0x67503030::
> > > +
> > > +       %p4ch   gP00 (0x67503030)
> > > +       %p4cn   00Pg (0x30305067)
> >
> > This doesn't look right to me, as network byte order is big endian?
> > Note that I didn't check the code.
>
> Yes, network is big endian and this seems right to me. What is the confusion?

On a big-endian machine, it should print 0x67503030, like the host
or explicit big-endian output.

> > > +       %p4cl   00Pg (0x30305067)
> > > +       %p4cb   gP00 (0x67503030)

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds