PowerPC alignment option

[Joel Sherrill]

I am throwing this suggestion out for comments.
The double patch to vfprintf.c was merged in
the main newlib regardless but this is more general.


-------- Original Message --------
From: Sergei Organov <osv at javad.ru>
Subject: Re: vfprintf.c patch
To: Joel Sherrill <joel.sherrill at OARcorp.com>

Joel Sherrill <joel.sherrill at OARcorp.com> writes:


[...]

> Unfortunately, I think gcc breaks this rule on some ports.  I recall
> the HPPA using the FPU for integer multiplies.  And I recall someone
> reporting on the RTEMS list that the PowerPC would do moves of
> 8-byte structures with FP load/stores.

Joel, it was I who reported this.

I just want to let you know that it seems this behavior could be
prevented by
using -mstrict-align option to the powerpc-rtems-gcc. I now think that
it's
probably a good idea to add this option to the gcc command line for
PowerPC
BSPs, as there is no real "alignment exception" handler in the BSPs that
will
fix unaligned accesses, so -mstrict-align should be appropriate anyway.

BR,
Sergei Organov.