From: Nai Xia <nai.xia@gmail.com>
To: Andi Kleen <ak@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Linux-MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Question about missing "cld" in x86 string assembly code
Date: Sat, 17 Dec 2011 22:52:26 +0800 [thread overview]
Message-ID: <201112172252.26439.nai.xia@gmail.com> (raw)
Hi,
I notice that all x86 assembly code for string operations containing
"scasb, lodsb", etc does not have "cld" at the beginning.
Is this 100% safe?
Or in other words, how could we be sure that
there is no "std" generated by compiler somewhere just before
the string operations?
Thanks,
Nai
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next reply other threads:[~2011-12-17 14:52 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-17 14:52 Nai Xia [this message]
-- strict thread matches above, loose matches on Subject: below --
2011-12-17 14:58 Question about missing "cld" in x86 string assembly code Nai Xia
2011-12-17 17:08 ` Brian Gerst
2011-12-17 18:39 ` Linus Torvalds
2011-12-22 15:52 ` nai.xia
2011-12-22 15:34 ` nai.xia
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