From: "H. Peter Anvin" <hpa@zytor.com>
To: Sheng Yang <sheng@linux.intel.com>
Cc: 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 07:09:24 -0700 [thread overview]
Message-ID: <4A0C2614.4010803@zytor.com> (raw)
In-Reply-To: <200905141152.29378.sheng@linux.intel.com>
Sheng Yang wrote:
>
> Yeah, this one also works well(lightly tested). :)
>
> But one thing should be noticed that, bit ops recognized the input as signed.
> According to SDM 2A 3.1.1.7 Operation Section, Bit(BitBase, BitOffset) can
> accept BitOffset as negative value, then search backward... Well, I indeed
> don't know when we need this, but I think keep signed here should be better...
>
Urk, you're right. How daft. I had preferred to switch it to unsigned
long to match MIPS and SPARC, but that probably is a good reason to
leave it signed. Pain.
-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: Sheng Yang <sheng@linux.intel.com>
Cc: 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 07:09:24 -0700 [thread overview]
Message-ID: <4A0C2614.4010803@zytor.com> (raw)
In-Reply-To: <200905141152.29378.sheng@linux.intel.com>
Sheng Yang wrote:
>
> Yeah, this one also works well(lightly tested). :)
>
> But one thing should be noticed that, bit ops recognized the input as signed.
> According to SDM 2A 3.1.1.7 Operation Section, Bit(BitBase, BitOffset) can
> accept BitOffset as negative value, then search backward... Well, I indeed
> don't know when we need this, but I think keep signed here should be better...
>
Urk, you're right. How daft. I had preferred to switch it to unsigned
long to match MIPS and SPARC, but that probably is a good reason to
leave it signed. Pain.
-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 14:09 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
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 [this message]
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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