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From: Scott Wood <scottwood@freescale.com>
To: u-boot@lists.denx.de
Subject: [U-Boot] io.h
Date: Tue, 5 Jan 2010 13:59:27 -0600	[thread overview]
Message-ID: <20100105195927.GA26296@loki.buserror.net> (raw)
In-Reply-To: <BEFE4DF574034B49B4B921F93110FCA6@CT.itrc.ac.ir>

On Sat, Dec 19, 2009 at 11:40:40AM +0330, seyyed morteza havaedgi wrote:
> I working on mpc8272. in the file io.h there is  "twi 0,RA,0" instruction.
> what this instruction means and what it does? In accordance with powerpc programmers manual this instruction must do nothing because the TO field is zero.

It turns a data dependency on RA into a flow control dependency (even though
the decision always ends up being not to trap), which can then be ordered by
a following isync.

-Scott

      reply	other threads:[~2010-01-05 19:59 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-12-19  8:10 [U-Boot] io.h seyyed morteza havaedgi
2010-01-05 19:59 ` Scott Wood [this message]

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