Subject: re: -mstrict-align on powerpc
To: Juergen Hannken-Illjes <firstname.lastname@example.org>
From: matthew green <email@example.com>
Date: 03/16/2003 22:35:24
On Sat, Mar 15, 2003 at 09:25:08PM -0800, Jason Thorpe wrote:
> On Saturday, March 15, 2003, at 08:09 AM, Juergen Hannken-Illjes wrote:
> >Module Name: src
> >Committed By: hannken
> >Date: Sat Mar 15 16:09:35 UTC 2003
> >Modified Files:
> > src/gnu/dist/toolchain/gcc/config/rs6000: netbsd.h
> >Log Message:
> >Add -mstrict-align to the CC1 default options.
> >At least the 403 ports cannot handle unaligned access.
> >Discussed with Jason Thorpe and Matt Thomas.
> Hm. Maybe what we should do is default to -mstrict-align, but disable
> -mstrict-align for -mcpu=foo where foo doesn't require strict alignment
> (e.g. 603, 604, 750, etc.). All of those CPUs can do unaligned access
> on integer loads/stores, right? Is it only the 403 that actually has
> the problem? (I honestly can't remember if the 405 can do unaligned
> access or not...)
From the sources (I have no walnut board) the 405 also traps.
At least 1.6 has a shared/powerpc with X, games and text.
Therefore the powerpc should use a feature set useable on all cpus.
that's OK; if someone uses -m603 they are doing that themselves
and it doesn't matter ... i think jason's idea is still useful.