Subject: Re: [PATCH 10/15] powerpc: fixes for instructions not using correct register naming

From: Andreas Schwab <[email-masked]>
Date: Sat, 09 Jun 2012 11:39:43 +0200

Benjamin Herrenschmidt <[email-masked]> writes:

> On Sat, 2012-06-09 at 08:53 +0200, Andreas Schwab wrote:
>> 
>> > The macro system we use cannot do that (it will prefix with REG_),
>> since
>> > both arguments are registers we must use R0 in this case.
>> 
>> So define a ___PPC_RA0 macro that doesn't do that.
>
> But then we lose the checking for other instructions :-)

??? There is no loss of checking for instructions that do not use
___PPC_RA0.

> Unless we start being nasty and defining a different macro form for RA
> which can be 0...

That's what ___PPC_RA0 is all about.

> I'd rather not go there unless we absolutely have to...

Having to use R0 for an insn that does *not* use r0 is clearly a step
backwards.

> What would be nice also would be if we had a gas option to enforce the
> use of % for register names.

If gas is ever changed that way you have to be explict about 0 vs. %r0
anyway.

Andreas.

-- 
Andreas Schwab, [email-masked]
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