Thread (19 messages) flat view 19 messages, 8 authors, 2007-05-25

Re: 440 ebony patch seems to have broken 85xx build on powerpc.git

From: David Gibson <hidden>
Date: 2007-05-25 01:30:05

On Fri, May 25, 2007 at 12:02:44AM +0200, Segher Boessenkool wrote:
quoted
quoted
quoted
Nothing is telling GCC what CPU to compile for, so it
will just use the compiler's default, which very likely
is not what you want.  For files that will only ever
be used on 440, the correct flags are -mcpu=440 -Wa,-m440 .
We could add that to the per-file flags already, right?
I think it should really use -mcpu=powerpc on all files.
The problem that Dave saw was the result of using a compiler
that defaults to -mcpu=8540, which uses instruction that
don't work on 440.
No, those options _do_ work on 440, but the -mbooke
assembler flag disallows isel (since it is an optional
insn).
But not on 440GP, which is what Ebony is.
quoted
The common files really need to be built with -mcpu flags that
make the code work on any system if you want to be able
to use just a single boot wrapper binary for all.
On any system where they can run at all, yes.  It should
be fine to compile a 440-only file with 440-specific flags.
-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson
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