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From: Segher Boessenkool <segher@kernel.crashing.org>
Subject: Re: 440 ebony patch seems to have broken 85xx build on powerpc.git
Date: Fri, 25 May 2007 00:08:28 +0200
To: Arnd Bergmann <arnd@arndb.de>
Cc: linuxppc-dev@ozlabs.org
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> 1. Pass -Wa,-many to gcc
> This will really allow any possible instruction to be assembled, 
> including
> the old POWER architecture, but also includes all the other strange
> stuff like -maltivec, -mspe, -me500, ...

And it doesn't prevent the compiler from compiling insns
that can never work on the platform; for example, the
compiler in the original bug report will happily put isel
insns all over the place.

> 2. protect the use of special instructions with .machine directives.
> You can write all the inline assemblies like
>
> 	.machine push
> 	.machine 440
> 	<440 specific instruction>
> 	.machine pop
>
> This should work in any reasonably recent version of binutils, meaning
> that we don't need to pass stuff like -Wa,-m440 any more.

[You don't need the assembler flag at all, just the compiler
flag -mcpu=440].

This of course works, but is ultra-silly to do in a file
that will never run on anything other than 440 systems.


Segher