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To: Sheng Yang <sheng@linux.intel.com>
Cc: linux-kernel@vger.kernel.org, linux-mm <linux-mm@kvack.org>,
       Ingo Molnar <mingo@elte.hu>, "H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH] x86: Extend test_and_set_bit() test_and_clean_bit() to 64 bits in X86_64
From: Andi Kleen <andi@firstfloor.org>
References: <1242202647-32446-1-git-send-email-sheng@linux.intel.com>
Date: Wed, 13 May 2009 10:38:29 +0200
In-Reply-To: <1242202647-32446-1-git-send-email-sheng@linux.intel.com> (Sheng Yang's message of "Wed, 13 May 2009 16:17:27 +0800")
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Sheng Yang <sheng@linux.intel.com> writes:

> -static inline int test_and_set_bit(int nr, volatile unsigned long *addr)
> +static inline int test_and_set_bit(long int nr, volatile unsigned long *addr)
>  {
>  	int oldbit;
>  
> -	asm volatile(LOCK_PREFIX "bts %2,%1\n\t"
> +	asm volatile(LOCK_PREFIX REX_X86 "bts %2,%1\n\t"

Use btsq on 64bit, then you don't need the explicit rex prefix.

-Andi

-- 
ak@linux.intel.com -- Speaking for myself only.