From: "H. Peter Anvin" <hpa@zytor.com>
To: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: akpm@linux-foundation.org, Ingo Molnar <mingo@elte.hu>,
linux-kernel@vger.kernel.org, Andi Kleen <andi@firstfloor.org>,
Rusty Russell <rusty@rustcorp.com.au>, Andi Kleen <ak@muc.de>,
Chuck Ebbert <cebbert@redhat.com>,
Christoph Hellwig <hch@infradead.org>,
Jeremy Fitzhardinge <jeremy@goop.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Adrian Bunk <bunk@stusta.de>,
Alexey Dobriyan <adobriyan@gmail.com>,
akpm@osdl.org
Subject: Re: [patch 13/17] Immediate Values - x86 Optimization
Date: Wed, 09 Apr 2008 15:33:38 -0700 [thread overview]
Message-ID: <47FD4442.3050000@zytor.com> (raw)
In-Reply-To: <20080409190816.GB30202@Krystal>
Mathieu Desnoyers wrote:
> * H. Peter Anvin (hpa@zytor.com) wrote:
>> Mathieu Desnoyers wrote:
>>> Ok, so the most flexible solution that I see, that should fit for both
>>> x86 and x86_64 would be :
>>> 1 byte : "=q" : "a", "b", "c", or "d" register for the i386. For
>>> x86-64 it is equivalent to "r" class (for 8-bit
>>> instructions that do not use upper halves).
>>> 2, 4, 8 bytes : "=r" : A register operand is allowed provided that it is
>>> in a
>>> general register.
>> Any reason to keep carrying this completely misleading comment chunk still?
>>
>> -hpa
>
> This comment explains why I use the =q constraint for the 1 bytes
> immediate value. It makes sure we use an instruction with 1-byte opcode,
> without REX.R prefix, on x86_64.
No, it doesn't. That would be "=Q".
-hpa
next prev parent reply other threads:[~2008-04-09 22:48 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-04-09 15:08 [patch 00/17] Text Edit Lock and Immediate Values for 2.6.25-rc8-mm1 Mathieu Desnoyers
2008-04-09 15:08 ` [patch 01/17] Kprobes - use a mutex to protect the instruction pages list Mathieu Desnoyers
2008-04-09 20:08 ` Masami Hiramatsu
2008-04-09 15:08 ` [patch 02/17] Kprobes - do not use kprobes mutex in arch code Mathieu Desnoyers
2008-04-09 20:08 ` Masami Hiramatsu
2008-04-09 15:08 ` [patch 03/17] Kprobes - declare kprobe_mutex static Mathieu Desnoyers
2008-04-09 20:08 ` Masami Hiramatsu
2008-04-09 15:08 ` [patch 04/17] x86 - Enhance DEBUG_RODATA support - alternatives Mathieu Desnoyers
2008-04-09 15:08 ` [patch 05/17] x86 Fix text_poke for vmalloced pages Mathieu Desnoyers
2008-04-09 15:08 ` [patch 06/17] x86 - Enhance DEBUG_RODATA support for hotplug and kprobes Mathieu Desnoyers
2008-04-09 15:08 ` [patch 07/17] Text Edit Lock - Architecture Independent Code Mathieu Desnoyers
2008-04-09 15:08 ` [patch 08/17] Text Edit Lock - kprobes architecture independent support Mathieu Desnoyers
2008-04-09 15:08 ` [patch 09/17] Add all cpus option to stop machine run Mathieu Desnoyers
2008-04-09 18:10 ` Alexey Dobriyan
2008-04-09 18:24 ` Andi Kleen
2008-04-10 3:34 ` Rusty Russell
2008-04-10 4:26 ` KOSAKI Motohiro
2008-04-09 18:54 ` Mathieu Desnoyers
2008-04-09 15:08 ` [patch 10/17] Immediate Values - Architecture Independent Code Mathieu Desnoyers
2008-04-09 15:08 ` [patch 11/17] Implement immediate update via stop_machine_run Mathieu Desnoyers
2008-04-10 8:04 ` KOSAKI Motohiro
2008-04-10 20:01 ` Mathieu Desnoyers
2008-04-11 4:50 ` KOSAKI Motohiro
2008-04-09 15:08 ` [patch 12/17] Immediate Values - Kconfig menu in EMBEDDED Mathieu Desnoyers
2008-04-10 3:23 ` Rusty Russell
2008-04-10 19:32 ` [patch 12/17] Immediate Values - Kconfig menu in EMBEDDED (updated) Mathieu Desnoyers
2008-04-10 21:54 ` Rusty Russell
2008-04-14 23:52 ` Mathieu Desnoyers
2008-04-09 15:08 ` [patch 13/17] Immediate Values - x86 Optimization Mathieu Desnoyers
2008-04-09 18:01 ` H. Peter Anvin
2008-04-09 19:08 ` Mathieu Desnoyers
2008-04-09 22:33 ` H. Peter Anvin [this message]
2008-04-10 0:42 ` Mathieu Desnoyers
2008-04-10 0:47 ` H. Peter Anvin
2008-04-09 20:21 ` [patch 13/17] Immediate Values - x86 Optimization (updated) Mathieu Desnoyers
2008-04-09 22:33 ` H. Peter Anvin
2008-04-09 23:15 ` Mathieu Desnoyers
2008-04-09 15:08 ` [patch 14/17] Add text_poke and sync_core to powerpc Mathieu Desnoyers
2008-04-09 15:08 ` [patch 15/17] Immediate Values - Powerpc Optimization Mathieu Desnoyers
2008-04-09 15:08 ` [patch 16/17] Immediate Values - Documentation Mathieu Desnoyers
2008-04-10 3:33 ` Rusty Russell
2008-04-11 1:16 ` Mathieu Desnoyers
2008-04-11 15:06 ` Rusty Russell
2008-04-15 0:12 ` Mathieu Desnoyers
2008-04-11 13:44 ` [RFC PATCH] Immediate Values Support init Mathieu Desnoyers
2008-04-09 15:08 ` [patch 17/17] Scheduler Profiling - Use Immediate Values Mathieu Desnoyers
2008-04-10 4:23 ` [patch 00/17] Text Edit Lock and Immediate Values for 2.6.25-rc8-mm1 KOSAKI Motohiro
2008-04-10 7:31 ` Takashi Nishiie
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