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Re: EABI stack alignment for ppc
- From: Geoffrey Keating <geoffk at geoffk dot org>
- To: Olivier Hainque <hainque at adacore dot com>
- Cc: gcc at gcc dot gnu dot org
- Date: 26 Apr 2005 15:49:10 -0700
- Subject: Re: EABI stack alignment for ppc
- References: <20050426152449.A20359@rome.act-europe.fr>
Olivier Hainque <email@example.com> writes:
> PPC EABI targets are currently configured with both BIGGEST_ALIGNMENT and
> PREFERRED_STACK_BOUNDARY set to 128, I believe to accomodate
> "a long double member within a structure or union shall start at the lowest
> available offset aligned on a 16byte boundary"
BIGGEST_ALIGNMENT is 128 for a number of reasons, but
PREFERRED_STACK_BOUNDARY is 128 primarily so that code compiled with
-meabi can also be used on Linux and other SVR4 targets, and for
> Now, I'm a bit unclear on the meaning of the ABI statement quoted above, and
> on the real implications this should have in the compiler.
> Does it imply that a long double field *address* should always be a multiple
> of 16, or just that the *offset* should be such a multiple ?
It says offset, so it probably means offset.