Re: Question on BIGGEST_ALIGNMENT in GCC on NetBSD/m68k
Hello Geert,
On Wed, 2025-06-18 at 11:56 +0200, Geert Uytterhoeven wrote:
> > Coldfire already uses a different alignment (for the stack):
> >
> > /* ColdFire and fido strongly prefer a 32-bit aligned stack. */
> > #define PREFERRED_STACK_BOUNDARY \
> > ((TARGET_COLDFIRE || TARGET_FIDOA) ? 32 : 16)
> >
> > It's instruction set is also not fully compatible AFAIK.
>
> Sure, but you will impact it regardless.
Could you please elaborate this a bit more, please?
Coldfire is handled as a separate target via TARGET_COLDFIRE in GCC, so we
would certainly be able to toggle the alignment settings independent of
what's done on classic m68k. In the Linux kernel, Coldfire is also a separate
arch, so the alignment settings can also be handled there separately if necessary.
It's not really necessary to enforce this on Coldfire. However, since buildroot
builds completely from source, it wouldn't even be a problem to change the alignment
there as well.
PS: I would like to lead a discussion on how to implement this properly and
not continue to have one why this shouldn't be done as the latter is continuing
to take a lot of energy.
Adrian
--
.''`. John Paul Adrian Glaubitz
: :' : Debian Developer
`. `' Physicist
`- GPG: 62FF 8A75 84E0 2956 9546 0006 7426 3B37 F5B5 F913
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