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From: "Woodhouse, David" <david.woodhouse@intel.com>
To: Rob Herring <robherring2@gmail.com>
Cc: Kim Phillips <kim.phillips@freescale.com>,
	Russell King <linux@arm.linux.org.uk>,
	Andrew Morton <akpm@linux-foundation.org>,
	Rusty Russell <rusty@rustcorp.com.au>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Daniel Santos <daniel.santos@pobox.com>,
	Borislav Petkov <bp@alien8.de>,
	David Rientjes <rientjes@google.com>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>
Subject: Re: [RFC] arm: use built-in byte swap function
Date: Tue, 29 Jan 2013 15:10:43 +0000	[thread overview]
Message-ID: <1359472241.3529.129.camel@shinybook.infradead.org> (raw)
In-Reply-To: <5107E285.8060304@gmail.com>

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On Tue, 2013-01-29 at 08:53 -0600, Rob Herring wrote:
> If you specify to use the builtin's, do you still get inline rev
> instructions emitted?

You mean from the architecture's __arch_swab32() et al. macros?

No. If the architecture enables ARCH_USE_BUILTIN_BSWAP and the compiler
version checks indicate that the correspondingly-sized builtin is
available, then the builtin will be used. Only if the arch *doesn't* set
ARCH_USE_BUILTIN_BSWAP, or if the compiler is old enough not to have the
corresponding intrinsic, will the inline assembler in the __arch_swabXX
macros get used.

Note, however, that there is no such compiler intrinsic for swahb32(),
which is where rev16 gets used. That's still being left to the inline
asm in all cases.

-- 
                   Sent with MeeGo's ActiveSync support.

David Woodhouse                            Open Source Technology Centre
David.Woodhouse@intel.com                              Intel Corporation




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WARNING: multiple messages have this Message-ID (diff)
From: david.woodhouse@intel.com (Woodhouse, David)
To: linux-arm-kernel@lists.infradead.org
Subject: [RFC] arm: use built-in byte swap function
Date: Tue, 29 Jan 2013 15:10:43 +0000	[thread overview]
Message-ID: <1359472241.3529.129.camel@shinybook.infradead.org> (raw)
In-Reply-To: <5107E285.8060304@gmail.com>

On Tue, 2013-01-29 at 08:53 -0600, Rob Herring wrote:
> If you specify to use the builtin's, do you still get inline rev
> instructions emitted?

You mean from the architecture's __arch_swab32() et al. macros?

No. If the architecture enables ARCH_USE_BUILTIN_BSWAP and the compiler
version checks indicate that the correspondingly-sized builtin is
available, then the builtin will be used. Only if the arch *doesn't* set
ARCH_USE_BUILTIN_BSWAP, or if the compiler is old enough not to have the
corresponding intrinsic, will the inline assembler in the __arch_swabXX
macros get used.

Note, however, that there is no such compiler intrinsic for swahb32(),
which is where rev16 gets used. That's still being left to the inline
asm in all cases.

-- 
                   Sent with MeeGo's ActiveSync support.

David Woodhouse                            Open Source Technology Centre
David.Woodhouse at intel.com                              Intel Corporation



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  reply	other threads:[~2013-01-29 15:10 UTC|newest]

Thread overview: 127+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-01-29  1:30 [RFC] arm: use built-in byte swap function Kim Phillips
2013-01-29  1:30 ` Kim Phillips
2013-01-29  8:35 ` Borislav Petkov
2013-01-29  8:35   ` Borislav Petkov
2013-01-29 16:46   ` Woodhouse, David
2013-01-29 16:46     ` Woodhouse, David
2013-01-29 17:42     ` Borislav Petkov
2013-01-29 17:42       ` Borislav Petkov
2013-01-29 17:55       ` Woodhouse, David
2013-01-29 17:55         ` Woodhouse, David
2013-01-29 18:10         ` Borislav Petkov
2013-01-29 18:10           ` Borislav Petkov
2013-01-30 10:22           ` Woodhouse, David
2013-01-30 10:22             ` Woodhouse, David
2013-01-31  2:09             ` Kim Phillips
2013-01-31  2:09               ` Kim Phillips
2013-01-31  6:44               ` Borislav Petkov
2013-01-31  6:44                 ` Borislav Petkov
2013-01-31  9:28               ` Russell King - ARM Linux
2013-01-31  9:28                 ` Russell King - ARM Linux
2013-01-31 20:59                 ` Kim Phillips
2013-01-31 20:59                   ` Kim Phillips
2013-01-31 21:33                   ` Borislav Petkov
2013-01-31 21:33                     ` Borislav Petkov
2013-01-31 22:11                   ` Woodhouse, David
2013-01-31 22:11                     ` Woodhouse, David
2013-02-01  0:37                     ` [PATCH v4] " Kim Phillips
2013-02-01  0:37                       ` Kim Phillips
2013-02-01 10:46                       ` Russell King - ARM Linux
2013-02-01 10:46                         ` Russell King - ARM Linux
2013-02-01  1:17                   ` [RFC] " Russell King - ARM Linux
2013-02-01  1:17                     ` Russell King - ARM Linux
2013-02-01  7:33                     ` Woodhouse, David
2013-02-01  7:33                       ` Woodhouse, David
2013-02-06  3:04                       ` Kim Phillips
2013-02-06  3:04                         ` Kim Phillips
2013-02-06  9:02                         ` Woodhouse, David
2013-02-06  9:02                           ` Woodhouse, David
2013-02-07  1:19                           ` Kim Phillips
2013-02-07  1:19                             ` Kim Phillips
2013-02-07 10:19                             ` Will Newton
2013-02-07 10:19                               ` Will Newton
2013-02-07 10:43                               ` Catalin Marinas
2013-02-07 10:43                                 ` Catalin Marinas
2013-02-07 18:13                             ` Russell King - ARM Linux
2013-02-07 18:13                               ` Russell King - ARM Linux
2013-02-08 17:25                               ` Woodhouse, David
2013-02-08 17:25                                 ` Woodhouse, David
2013-02-08 20:04                                 ` Nicolas Pitre
2013-02-08 20:04                                   ` Nicolas Pitre
2013-02-08 22:40                                   ` Woodhouse, David
2013-02-08 22:40                                     ` Woodhouse, David
2013-02-08 22:47                                     ` Nicolas Pitre
2013-02-08 22:47                                       ` Nicolas Pitre
2013-02-09  1:12                                       ` Kim Phillips
2013-02-09  1:12                                         ` Kim Phillips
2013-02-09  3:16                                         ` Nicolas Pitre
2013-02-09  3:16                                           ` Nicolas Pitre
2013-02-20  2:31                                           ` Kim Phillips
2013-02-20  2:31                                             ` Kim Phillips
2013-02-20  2:38                                             ` Stephen Boyd
2013-02-20  2:38                                               ` Stephen Boyd
2013-02-20  3:17                                             ` Nicolas Pitre
2013-02-20  3:17                                               ` Nicolas Pitre
2013-02-20 10:38                                               ` Woodhouse, David
2013-02-20 10:38                                                 ` Woodhouse, David
2013-02-20 13:36                                                 ` Nicolas Pitre
2013-02-20 13:36                                                   ` Nicolas Pitre
2013-02-20 13:44                                                   ` Woodhouse, David
2013-02-20 13:44                                                     ` Woodhouse, David
2013-02-20 14:06                                                     ` Nicolas Pitre
2013-02-20 14:06                                                       ` Nicolas Pitre
2013-02-20 14:53                                                       ` Woodhouse, David
2013-02-20 14:53                                                         ` Woodhouse, David
2013-02-20 15:43                                                         ` Nicolas Pitre
2013-02-20 15:43                                                           ` Nicolas Pitre
2013-02-21  3:49                                                           ` Kim Phillips
2013-02-21  3:49                                                             ` Kim Phillips
2013-02-21  4:29                                                             ` Nicolas Pitre
2013-02-21  4:29                                                               ` Nicolas Pitre
2013-02-21  6:52                                                               ` Kim Phillips
2013-02-21  6:52                                                                 ` Kim Phillips
2013-02-21 16:40                                                                 ` Nicolas Pitre
2013-02-21 16:40                                                                   ` Nicolas Pitre
2013-02-22  2:33                                                                   ` Kim Phillips
2013-02-22  2:33                                                                     ` Kim Phillips
2013-02-22  3:40                                                                     ` Nicolas Pitre
2013-02-22  3:40                                                                       ` Nicolas Pitre
2013-02-23  1:40                                                                       ` [PATCH v6] " Kim Phillips
2013-02-23  1:40                                                                         ` Kim Phillips
2013-02-23  2:40                                                                         ` Nicolas Pitre
2013-02-23  2:40                                                                           ` Nicolas Pitre
2013-02-23 23:20                                                                         ` Woodhouse, David
2013-02-23 23:20                                                                           ` Woodhouse, David
2013-05-23 16:46                                                                           ` [PATCH v7] " Kim Phillips
2013-05-23 16:46                                                                             ` Kim Phillips
2013-05-23 20:09                                                                             ` Nicolas Pitre
2013-05-23 20:09                                                                               ` Nicolas Pitre
2013-05-23 23:13                                                                             ` Russell King - ARM Linux
2013-05-23 23:13                                                                               ` Russell King - ARM Linux
2013-06-06 22:12                                                                               ` Russell King - ARM Linux
2013-06-06 22:12                                                                                 ` Russell King - ARM Linux
2013-06-06 22:23                                                                                 ` Borislav Petkov
2013-06-06 22:23                                                                                   ` Borislav Petkov
2013-06-07  0:03                                                                                 ` Stephen Rothwell
2013-06-07  0:03                                                                                   ` Stephen Rothwell
2013-05-26  5:38                                                                             ` Dirk Behme
2013-05-26  9:30                                                                               ` Woodhouse, David
2013-10-27  2:41                                                                             ` Nicolas Pitre
2013-10-27  2:41                                                                               ` Nicolas Pitre
2013-11-05 21:45                                                                               ` Kim Phillips
2013-11-05 21:45                                                                                 ` Kim Phillips
2013-02-21 16:37                                                               ` [RFC] " Woodhouse, David
2013-02-21 16:37                                                                 ` Woodhouse, David
2013-02-21 17:27                                                                 ` Nicolas Pitre
2013-02-21 17:27                                                                   ` Nicolas Pitre
2013-03-13 13:35                                             ` Woodhouse, David
2013-03-13 13:35                                               ` Woodhouse, David
2013-01-29 14:13 ` Russell King - ARM Linux
2013-01-29 14:13   ` Russell King - ARM Linux
2013-01-29 14:43   ` Woodhouse, David
2013-01-29 14:43     ` Woodhouse, David
2013-01-29 14:53 ` Rob Herring
2013-01-29 14:53   ` Rob Herring
2013-01-29 15:10   ` Woodhouse, David [this message]
2013-01-29 15:10     ` Woodhouse, David
2013-01-31 11:44 Woodhouse, David

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