This is the mail archive of the
mailing list for the GCC project.
Re: f/target.c HOST_BYTES_BIG_ENDIAN
- From: Hans-Peter Nilsson <hp at bitrange dot com>
- To: Alan Modra <amodra at bigpond dot net dot au>
- Cc: <gcc at gcc dot gnu dot org>, <gcc-patches at gcc dot gnu dot org>
- Date: Thu, 22 Aug 2002 22:32:07 -0400 (EDT)
- Subject: Re: f/target.c HOST_BYTES_BIG_ENDIAN
On Fri, 23 Aug 2002, Alan Modra wrote:
> On Thu, Aug 22, 2002 at 09:33:58AM -0400, Hans-Peter Nilsson wrote:
> > On Thu, 22 Aug 2002, Alan Modra wrote:
> > > HOST_BYTES_BIG_ENDIAN and HOST_BITS_BIG_ENDIAN are referenced in
> > > f/target.c when cross-compiling, but are not defined anywhere.
> > That sounds strange (for a BE host). f/target.c does include
> > config.h which includes auto-host.h...
> HOST_WORDS_BIG_ENDIAN is the only HOST_*_BIG_ENDIAN macro defined.
> grep the source.
Bummer. I added tests for macros that are not there. So only a
subset of the host <=> target mismatch situation is detectable:
HOST_WORDS_BIG_ENDIAN <=> BYTES_BIG_ENDIAN. The semantics for
the host vs. target macros are a little different;
HOST_WORDS_BIG_ENDIAN implies the hostness *BYTES*_BIG_ENDIAN
but also the host *WORDS*_BIG_ENDIAN. And apparently nothing
else has a need to test these host endian details so it doesn't
seem worthwhile to actually autoconf for it. Ugh.
Your patch is wrong; don't use the *target* BITS_BIG_ENDIAN (et
al) when the HOST_ one isn't defined. I suggest to remove that
test; check instead that HOST_WORDS_BIG_ENDIAN matches both
BYTES_BIG_ENDIAN and WORDS_BIG_ENDIAN. I see there's also a
(Heh, it seems few people use big-endian hosts for
> > There doesn't seem to be
> > anything magic about NATIVE_CROSS. What am I missing?
> Belts and braces. Strictly speaking, it's not necessary with the
> other changes.
Well it's confusing. I think there should be no NATIVE_CROSS
test. (Actually it's the wrong direction of the belts and
braces; belts and braces would have been to remove the #ifdef
CROSS_COMPILE and *always* test for endian mismatch. ;-)