Re: [PATCH] staging: rtl8723bs: Replace `& 0xfff` with `% 4096u`

From: Andy Shevchenko
Date: Fri Apr 11 2025 - 08:54:15 EST


On Fri, Apr 11, 2025 at 1:37 PM Dan Carpenter <dan.carpenter@xxxxxxxxxx> wrote:
> On Thu, Apr 10, 2025 at 08:43:53PM +0300, Andy Shevchenko wrote:
> >
> > > $ make drivers/staging/rtl8723bs/core/rtw_xmit.o
> > > $ cmp rtw_xmit_before.o rtw_xmit_after.o
> >
> > cmp is good but not good enough in general. Here it shows the 1:1
> > binary, but in some cases code can be the same, while binaries are
> > different. To make sure the code is the same use the bloat-o-meter
> > tool instead.
>
> I don't understand what you're saying at all. cmp shows that the compiler
> was automaticall tanslating the "& 0xfff" into "% 04096u" so the resulting
> object files are exactly the same.

There is a possibility that the compiler changes the code to the
equivalent and cmp will break, bloat-o-meter will check at least what
happened to the size of the *code*. object file is not only a code. It
may also contain debug symbols and other stuff which may break cmp,
while the code can be *the same*.

> ./scripts/bloat-o-meter just looks at the sizes so it's less useful in
> this case.



--
With Best Regards,
Andy Shevchenko