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):
> >=20
> > /* ColdFire and fido strongly prefer a 32-bit aligned stack.  */
> > #define PREFERRED_STACK_BOUNDARY \
> >   ((TARGET_COLDFIRE || TARGET_FIDOA) ? 32 : 16)
> >=20
> > It's instruction set is also not fully compatible AFAIK.
>=20
> 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 separa=
te
arch, so the alignment settings can also be handled there separately if nec=
essary.

It's not really necessary to enforce this on Coldfire. However, since build=
root
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 contin=
uing
to take a lot of energy.

Adrian

--=20
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer
`. `'   Physicist
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