From: "H. Peter Anvin" <hpa@zytor.com>
To: Andi Kleen <andi@firstfloor.org>
Cc: Sheng Yang <sheng@linux.intel.com>,
linux-kernel@vger.kernel.org, linux-mm <linux-mm@kvack.org>,
Ingo Molnar <mingo@elte.hu>
Subject: Re: [PATCH] x86: Extend test_and_set_bit() test_and_clean_bit() to 64 bits in X86_64
Date: Thu, 14 May 2009 07:16:10 -0700 [thread overview]
Message-ID: <4A0C27AA.4010006@zytor.com> (raw)
In-Reply-To: <20090514141649.GD10933@one.firstfloor.org>
Andi Kleen wrote:
>>>
>> The right way to do it is to pass the proper type of register.
>
> For the input index register you don't actually need 64bit and for the
> value it's typically memory anyways.
>
If you have a 64-bit operation you have a 64-bit index register. And
you need a 64-bit index for it to handle over 2^31 (since it is signed.)
-hpa
--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.
WARNING: multiple messages have this Message-ID (diff)
From: "H. Peter Anvin" <hpa@zytor.com>
To: Andi Kleen <andi@firstfloor.org>
Cc: Sheng Yang <sheng@linux.intel.com>,
linux-kernel@vger.kernel.org, linux-mm <linux-mm@kvack.org>,
Ingo Molnar <mingo@elte.hu>
Subject: Re: [PATCH] x86: Extend test_and_set_bit() test_and_clean_bit() to 64 bits in X86_64
Date: Thu, 14 May 2009 07:16:10 -0700 [thread overview]
Message-ID: <4A0C27AA.4010006@zytor.com> (raw)
In-Reply-To: <20090514141649.GD10933@one.firstfloor.org>
Andi Kleen wrote:
>>>
>> The right way to do it is to pass the proper type of register.
>
> For the input index register you don't actually need 64bit and for the
> value it's typically memory anyways.
>
If you have a 64-bit operation you have a 64-bit index register. And
you need a 64-bit index for it to handle over 2^31 (since it is signed.)
-hpa
--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.
--
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next prev parent reply other threads:[~2009-05-14 14:16 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-05-13 8:17 [PATCH] x86: Extend test_and_set_bit() test_and_clean_bit() to 64 bits in X86_64 Sheng Yang
2009-05-13 8:17 ` Sheng Yang
2009-05-13 8:38 ` Andi Kleen
2009-05-13 8:38 ` Andi Kleen
2009-05-14 3:45 ` Sheng Yang
2009-05-14 3:45 ` Sheng Yang
2009-05-14 8:32 ` Andi Kleen
2009-05-14 8:32 ` Andi Kleen
2009-05-14 14:09 ` H. Peter Anvin
2009-05-14 14:09 ` H. Peter Anvin
2009-05-14 14:16 ` Andi Kleen
2009-05-14 14:16 ` Andi Kleen
2009-05-14 14:16 ` H. Peter Anvin [this message]
2009-05-14 14:16 ` H. Peter Anvin
2009-05-14 14:27 ` Andi Kleen
2009-05-14 14:27 ` Andi Kleen
2009-05-14 14:25 ` H. Peter Anvin
2009-05-14 14:25 ` H. Peter Anvin
2009-05-14 14:33 ` Andi Kleen
2009-05-14 14:33 ` Andi Kleen
2009-05-14 14:36 ` H. Peter Anvin
2009-05-14 14:36 ` H. Peter Anvin
2009-05-13 16:18 ` H. Peter Anvin
2009-05-13 16:55 ` H. Peter Anvin
2009-05-13 16:55 ` H. Peter Anvin
2009-05-13 17:29 ` H. Peter Anvin
2009-05-14 3:52 ` Sheng Yang
2009-05-14 3:52 ` Sheng Yang
2009-05-14 14:09 ` H. Peter Anvin
2009-05-14 14:09 ` H. Peter Anvin
2009-05-14 13:57 ` Christoph Hellwig
2009-05-14 13:57 ` Christoph Hellwig
2009-05-14 14:29 ` H. Peter Anvin
2009-05-14 14:29 ` H. Peter Anvin
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