From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <3E54544E.2040804@embeddededge.com> Date: Wed, 19 Feb 2003 23:06:38 -0500 From: Dan Malek MIME-Version: 1.0 To: Joakim Tjernlund Cc: linuxppc-embedded@lists.linuxppc.org Subject: Re: lmw and stmw instructions not used copy functions References: <004f01c2d861$c6cdab30$020120b0@jockeXP> Content-Type: text/plain; charset=us-ascii; format=flowed Sender: owner-linuxppc-embedded@lists.linuxppc.org List-Id: Joakim Tjernlund wrote: > I noticed that the lmw and stmw instructions are not used in copy_page(), clear_page() etc. > Aren't these instructions faster than a bunch of lwz/stw? Motorola doesn't guarantee these are any faster, and most documentation indicates they are likely to be slower. If you look closely, you may notice that not too many places can utilize these instructions, and often the load or store is done to take advantages of some pipeline optimizations with comparisons to values in well known registers. -- Dan ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/