From: "H. Peter Anvin" <hpa@zytor.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
linux-kernel@vger.kernel.org, Ingo Molnar <mingo@elte.hu>,
Andrew Morton <akpm@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Frederic Weisbecker <fweisbec@gmail.com>,
Jason Baron <jbaron@redhat.com>
Subject: Re: [PATCH 2/2] jump labels/x86: Use etiher 5 byte or 2 byte jumps
Date: Thu, 19 Jan 2012 06:58:09 -0800 [thread overview]
Message-ID: <4F182F81.2020200@zytor.com> (raw)
In-Reply-To: <1326984993.17534.125.camel@gandalf.stny.rr.com>
On 01/19/2012 06:56 AM, Steven Rostedt wrote:
>>
>> Is it possible that the compiler choose a jump that is not 2 or 5-byte ?
>> e.g. a jmp rel16 (e9 opcode) on 32-bit x86, or any of the other
>
> Isn't e9 the 5 byte opcode?
>
I think Mathieu is thinking of 66 e9 rel16 (66 e9 xx xx) which isn't
used by the compiler since it truncates the result to 16 bits.
-hpa
prev parent reply other threads:[~2012-01-19 14:58 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-18 19:53 [PATCH 0/2] [RFC] jump-label/x86: Compress jmps to 2 bytes where possible Steven Rostedt
2012-01-18 19:53 ` [PATCH 1/2] jump labels: Add infrastructure to update jump labels at compile time Steven Rostedt
2012-01-19 14:24 ` Mathieu Desnoyers
2012-01-19 14:52 ` Steven Rostedt
2012-01-18 19:53 ` [PATCH 2/2] jump labels/x86: Use etiher 5 byte or 2 byte jumps Steven Rostedt
2012-01-19 12:22 ` Ingo Molnar
2012-01-19 14:41 ` Mathieu Desnoyers
2012-01-19 14:46 ` H. Peter Anvin
2012-01-19 14:58 ` Steven Rostedt
2012-01-19 15:19 ` Steven Rostedt
2012-01-19 14:56 ` Steven Rostedt
2012-01-19 14:58 ` H. Peter Anvin [this message]
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