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Re: How to implement atomic swap with asm on PowerPC
- From: Chaoran Yang <chaoran at rice dot edu>
- To: Andrew Haley <aph at redhat dot com>
- Cc: gcc-help <gcc-help at gcc dot gnu dot org>
- Date: Thu, 23 Apr 2015 12:29:04 -0500
- Subject: Re: How to implement atomic swap with asm on PowerPC
- Authentication-results: sourceware.org; auth=none
- References: <B50248DD-7243-4264-8281-5552DDDA4789 at rice dot edu> <553926AF dot 9050507 at redhat dot com>
I see. Thanks very much!
Chaoran
> On Apr 23, 2015, at 12:06 PM, Andrew Haley <aph@redhat.com> wrote:
>
> On 04/23/2015 05:58 PM, Chaoran Yang wrote:
>> Since I specified ptr as an input, I assume GCC should not try to reuse the register. Am I missing a constraint here? What should I do to tell GCC to not to use the same register for ldarx instruction?
>
> Your output needs an earlyclobber. : "=&r" (old)
>
> Andrew.
>
>