Subject: Re: powerpc gcc alignment problem
To: Jason Thorpe <thorpej@nas.nasa.gov>
From: David Edelsohn <dje@watson.ibm.com>
List: tech-toolchain
Date: 01/13/2000 20:23:36
>>>>> Jason Thorpe writes:
Jason> Technically speaking, the PowerPC *does* have strict alignment, because
Jason> unaligned accesses require fixups (right? Or, did I totally misunderstand
Jason> that part of the book when I read it...)
You misunderstood the architecture book or you are mixing pieces
of information out of context. Most unaligned accesses on PowerPC
operating in big-endian mode do not require expensive fixups.
Enabling STRICT_ALIGNMENT has much more severe impact and
consequences than you seem to understand. It will change GCC's behavior
in an incompatible way with previous releases of GCC on NetBSD and will
make NetBSD incompatible with all other GCC PowerPC targets, including AIX
and Linux/PPC.
David