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From: Scott Wood <scottwood@freescale.com>
To: Paul Mackerras <paulus@samba.org>
Cc: mikey@neuling.org, michael@ellerman.id.au,
	Anton Blanchard <anton@samba.org>,
	olof@lixom.net, linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH] powerpc: Optimise the 64bit optimised __clear_user
Date: Thu, 7 Jun 2012 12:51:04 -0500	[thread overview]
Message-ID: <4FD0EA08.7040903@freescale.com> (raw)
In-Reply-To: <20120607030423.GA30053@drongo>

On 06/06/2012 10:04 PM, Paul Mackerras wrote:
> On Wed, Jun 06, 2012 at 06:40:54PM +0200, Segher Boessenkool wrote:
>>> +err1;	dcbz	r0,r3
>>
>> There is no such instruction, you probably meant "dcbz 0,r3"?
> 
> There certainly is such an instruction, though it doesn't do exactly
> what a naive reader might expect.  Using 0 rather than r0 or %r0
> improves readability but makes no difference to the assembler or the
> cpu.

The assembler can't tell that you used r0 rather than 0, because that's
handled by the preprocessor, but it seems like a bug (or at least lax
error checking) that it accepts %r0 there, and that objdump decodes it
as "dcbz r0,r3" rather than "dcbz 0,r3".

It's also odd that objdump produces output containing "r3" (not %r3)
when the assembler won't directly accept it.

-Scott

  reply	other threads:[~2012-06-07 17:51 UTC|newest]

Thread overview: 63+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-06-04  7:58 [PATCH] powerpc: Optimise the 64bit optimised __clear_user Anton Blanchard
2012-06-04 13:12 ` Olof Johansson
2012-06-04 14:44   ` Kumar Gala
2012-06-05  2:02 ` Anton Blanchard
2012-06-06 16:40   ` Segher Boessenkool
2012-06-06 21:20     ` Benjamin Herrenschmidt
2012-06-07  6:05       ` Michael Neuling
2012-06-07  6:07         ` Michael Ellerman
2012-06-07  6:12           ` Michael Neuling
2012-06-07  6:18             ` Michael Ellerman
2012-06-07 23:52               ` [PATCH] powerpc: Fix sldi to take literal not register name Michael Neuling
2012-06-08  0:19                 ` Benjamin Herrenschmidt
2012-06-07  6:39         ` [PATCH] powerpc: Optimise the 64bit optimised __clear_user Benjamin Herrenschmidt
2012-06-07  8:41           ` David Laight
2012-06-08 11:36       ` [PATCH 0/15] powerpc: convert GPR usage to %r0-31 and R0-31 Michael Neuling
2012-06-08 11:36         ` [PATCH 2/15] powerpc: modify macro ready for %r0 register change Michael Neuling
2012-06-08 11:36         ` [PATCH 14/15] powerpc: Introduce new __REG_R macros Michael Neuling
2012-06-08 11:36         ` [PATCH 5/15] powerpc: convert to %r for all GPR usage Michael Neuling
2012-06-08 21:54           ` Jesse Larrew
2012-06-14  3:25             ` Michael Neuling
2012-06-14  6:50               ` Jesse Larrew
2012-06-08 11:36         ` [PATCH 6/15] powerpc/pasemi: move lbz/stbciz to ppc-opcode.h Michael Neuling
2012-06-08 11:36         ` [PATCH 1/15] powerpc: Add defines for R0-R31 Michael Neuling
2012-06-08 11:36         ` [PATCH 12/15] powerpc: introduce new ___PPC_RA/B/S/T macros Michael Neuling
2012-06-08 11:36         ` [PATCH 4/15] powerpc: Fix sldi to take literal not register name Michael Neuling
2012-06-08 11:36         ` [PATCH 15/15] powerpc: enforce usage of R0-R31 where possible Michael Neuling
2012-06-08 11:36         ` [PATCH 13/15] powerpc: start using ___PPC_RA/B/S/T where necessary Michael Neuling
2012-06-08 11:36         ` [PATCH 7/15] powerpc: merge STK_REG/PARAM/FRAMESIZE Michael Neuling
2012-06-08 11:36         ` [PATCH 3/15] powerpc: fix usage of register macros getting ready for %r0 change Michael Neuling
2012-06-08 11:36         ` [PATCH 9/15] powerpc: change LOAD_REG_ADDR to use real register names Michael Neuling
2012-06-08 11:36         ` [PATCH 10/15] powerpc: fixes for instructions not using correct register naming Michael Neuling
2012-06-08 11:36         ` [PATCH 8/15] powerpc: change mtcrf to use real register names Michael Neuling
2012-06-08 11:36         ` [PATCH 11/15] powerpc: fix VSX macros so register names aren't wrapped Michael Neuling
     [not found]         ` <20120608113605.80B73D43B2B__2857.47079547054$1339155968$gmane$org@localhost.localdomain>
2012-06-08 12:12           ` [PATCH 7/15] powerpc: merge STK_REG/PARAM/FRAMESIZE Andreas Schwab
     [not found]         ` <20120608113605.91B88D43B2F__24549.446340143$1339156128$gmane$org@localhost.localdomain>
2012-06-08 12:15           ` [PATCH 10/15] powerpc: fixes for instructions not using correct register naming Andreas Schwab
2012-06-08 22:42             ` Benjamin Herrenschmidt
2012-06-09  6:53               ` Andreas Schwab
2012-06-09  7:17                 ` Benjamin Herrenschmidt
2012-06-09  9:39                   ` Andreas Schwab
2012-06-14  6:15                     ` [PATCH 0/18] powerpc: convert GPR usage to %r0-31 and R0-31 Michael Neuling
2012-06-14  6:15                       ` [PATCH 1/18] powerpc: Add defines for R0-R31 Michael Neuling
2012-06-14  6:15                       ` [PATCH 2/18] powerpc: modify macro ready for %r0 register change Michael Neuling
2012-06-14  6:15                       ` [PATCH 3/18] powerpc: fix usage of register macros getting ready for %r0 change Michael Neuling
2012-06-14  6:15                       ` [PATCH 4/18] powerpc: Fix sldi to take literal not register name Michael Neuling
2012-06-14  6:15                       ` [PATCH 5/18] powerpc: convert to %r for all GPR usage Michael Neuling
2012-06-14  6:15                       ` [PATCH 6/18] powerpc/pasemi: move lbz/stbciz to ppc-opcode.h Michael Neuling
2012-06-14  6:15                       ` [PATCH 7/18] powerpc: merge STK_REG/PARAM/FRAMESIZE Michael Neuling
2012-06-14  6:15                       ` [PATCH 8/18] powerpc: merge VCPU_GPR Michael Neuling
2012-06-14  6:15                       ` [PATCH 9/18] powerpc: change mtcrf to use real register names Michael Neuling
2012-06-14  6:15                       ` [PATCH 10/18] powerpc: change LOAD_REG_ADDR " Michael Neuling
2012-06-14  6:15                       ` [PATCH 11/18] powerpc: fixes for instructions not using correct register naming Michael Neuling
2012-06-14  6:15                       ` [PATCH 12/18] powerpc: fix VSX macros so register names aren't wrapped Michael Neuling
2012-06-14  6:15                       ` [PATCH 13/18] powerpc: introduce new ___PPC_RA/B/S/T macros Michael Neuling
2012-06-14  6:15                       ` [PATCH 14/18] powerpc: start using ___PPC_RA/B/S/T where necessary Michael Neuling
2012-06-14  6:15                       ` [PATCH 15/18] powerpc: Introduce new __REG_R macros Michael Neuling
2012-06-14  6:15                       ` [PATCH 16/18] powerpc: enforce usage of R0-R31 where possible Michael Neuling
2012-06-14  6:15                       ` [PATCH 17/18] powerpc: Add defines for RA 0-R31 Michael Neuling
2012-06-14  6:15                       ` [PATCH 18/18] powerpc: enforce usage of RA 0-R31 where possible Michael Neuling
2012-06-07  3:04     ` [PATCH] powerpc: Optimise the 64bit optimised __clear_user Paul Mackerras
2012-06-07 17:51       ` Scott Wood [this message]
2012-06-08  0:51         ` Benjamin Herrenschmidt
2012-06-08  7:34         ` Andreas Schwab
2012-06-07  0:30   ` Olof Johansson

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