linux-kernel - Re: [PATCH] powerpc: Fixed duplicate copying in the early boot.

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Date: Tue, 18 Jun 2024 22:12:54 +1000
From: Michael Ellerman <mpe@...erman.id.au>
To: Segher Boessenkool <segher@...nel.crashing.org>, Jinglin Wen
 <jinglin.wen@...ngroup.cn>
Cc: npiggin@...il.com, masahiroy@...nel.org, linux-kernel@...r.kernel.org,
 christophe.leroy@...roup.eu, naveen.n.rao@...ux.ibm.com,
 linuxppc-dev@...ts.ozlabs.org
Subject: Re: [PATCH] powerpc: Fixed duplicate copying in the early boot.

Segher Boessenkool <segher@...nel.crashing.org> writes:
> Hi!
>
> On Mon, Jun 17, 2024 at 10:35:09AM +0800, Jinglin Wen wrote:
>> +	cmplwi	cr0,r4,0	/* runtime base addr is zero */
>
> Just write
>    cmpwi r4,0
>
> cr0 is the default, also implicit in many other instructions, please
> don't clutter the source code.  All the extra stuff makes you miss the
> things that do matter!
>
> The "l" is unnecessary, you only care about equality here after all.

In my mind it's an unsigned comparison, so I'd use cmpld, even though as
you say all we actually care about is equality.

cheers