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From: Segher Boessenkool <segher@kernel.crashing.org>
Subject: Re: [PATCH 5/6] Support for the Ebony 440GP reference board in
	arch/powerpc
Date: Sun, 6 May 2007 03:58:34 +0200
To: David Gibson <david@gibson.dropbear.id.au>
Cc: Olof Johansson <olof@lixom.net>, ppcdev <linuxppc-dev@ozlabs.org>,
	Milton Miller <miltonm@bga.com>
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>>> How?   CPP doesn't apply inside the strings.
>>
>> So put it outside the strings:
>>
>> +     asm volatile (
>> +             "mfspr  %0," #SPRN_DBCR0 "\n\t"
>> +             "oris   %0,%0," #DBCR0_RST_SYSTEM "@h\n\t"
>> +             "mtspr  " #SPRN_DBCR0 ",%0"
>> +             : "=&r"(tmp));
>
> Um, I think stringify(SPRN_DBCR0) is needed there, not just a bare #.

Yes of course.  Someone is paying attention ;-) (*)

> At which point it's not entirely clear to be that just using the "i"
> constraint isn't the simplest option after all.

Sure.  Or even hardcoding the values (with comments),
which would show why a bare "oris" is correct at all.


Segher




(*) ... just not me