From mboxrd@z Thu Jan 1 00:00:00 1970 Path: main.gmane.org!not-for-mail From: Marius Vollmer Newsgroups: gmane.lisp.guile.user Subject: Re: OT: x86 assembly timings/size Date: Mon, 17 Nov 2003 22:27:45 +0100 Sender: guile-user-bounces+guile-user=m.gmane.org@gnu.org Message-ID: <871xs6r8ha.fsf@zagadka.ping.de> References: <8765hnf308.fsf@zagadka.ping.de> <1068823738.13123.54.camel@localhost> <20031114155148.GI16650@powergnu.laas.fr> <1069058032.1638.21.camel@localhost> <874qx3rogk.fsf@zagadka.ping.de> <87u153q8yk.fsf@zagadka.ping.de> <87n0avq7pf.fsf@zagadka.ping.de> <20031117164819.GA28322@mv3d.com> <878ymeri6x.fsf@zagadka.ping.de> <20031117191748.GA28701@mv3d.com> NNTP-Posting-Host: deer.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: sea.gmane.org 1069104788 14921 80.91.224.253 (17 Nov 2003 21:33:08 GMT) X-Complaints-To: usenet@sea.gmane.org NNTP-Posting-Date: Mon, 17 Nov 2003 21:33:08 +0000 (UTC) Original-X-From: guile-user-bounces+guile-user=m.gmane.org@gnu.org Mon Nov 17 22:33:06 2003 Return-path: Original-Received: from monty-python.gnu.org ([199.232.76.173]) by deer.gmane.org with esmtp (Exim 3.35 #1 (Debian)) id 1ALqza-0002os-00 for ; Mon, 17 Nov 2003 22:33:06 +0100 Original-Received: from localhost ([127.0.0.1] helo=monty-python.gnu.org) by monty-python.gnu.org with esmtp (Exim 4.24) id 1ALrto-0007WG-Bv for guile-user@m.gmane.org; Mon, 17 Nov 2003 17:31:12 -0500 Original-Received: from list by monty-python.gnu.org with tmda-scanned (Exim 4.24) id 1ALrsV-0007VE-0Q for guile-user@gnu.org; Mon, 17 Nov 2003 17:29:51 -0500 Original-Received: from mail by monty-python.gnu.org with spam-scanned (Exim 4.24) id 1ALrry-0007Ji-1P for guile-user@gnu.org; Mon, 17 Nov 2003 17:29:49 -0500 Original-Received: from [195.253.8.218] (helo=mail.dokom.net) by monty-python.gnu.org with esmtp (Exim 4.24) id 1ALrrx-0007JI-Mi for guile-user@gnu.org; Mon, 17 Nov 2003 17:29:17 -0500 Original-Received: from dialin.speedway42.dip10.dokom.de ([195.138.42.10] helo=zagadka.ping.de) by mail.dokom.net with smtp (Exim 3.36 #3) id 1ALqxI-0002vl-00 for guile-user@gnu.org; Mon, 17 Nov 2003 22:30:44 +0100 Original-Received: (qmail 2469 invoked by uid 1000); 17 Nov 2003 21:27:45 -0000 Original-To: guile-user@gnu.org In-Reply-To: <20031117191748.GA28701@mv3d.com> (Allister MacLeod's message of "Mon, 17 Nov 2003 14:17:48 -0500") User-Agent: Gnus/5.1002 (Gnus v5.10.2) Emacs/21.3 (gnu/linux) X-BeenThere: guile-user@gnu.org X-Mailman-Version: 2.1.2 Precedence: list List-Id: General Guile related discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: guile-user-bounces+guile-user=m.gmane.org@gnu.org Xref: main.gmane.org gmane.lisp.guile.user:2405 X-Report-Spam: http://spam.gmane.org/gmane.lisp.guile.user:2405 Allister MacLeod writes: > I forget the original expansion of lea.. maybe load extended > address? My guess would be "load effective address"... but it's not _really_ relevant, right? :-) > I really ought to go look at an assembly reference myself. A brief > google for "x86 assembly timings lea" didn't turn up anything > immediately and eminently useful in the first few hits. I doubt that there are any simple and reliable timing diagrams for IA-32 instructions in general. I would imagine tho that lea uses the addressing unit while shl goes thru the regular integer unit, on chips that make the distinction. It's all pretty idle speculation on my part, tho. Assembler used to be fun on the 68k but I've never written more than three consecutive lines of x86 assembler. > Anyway, probably the one with just lea's is slightly faster. > Certainly unless the D=R1+R2*N instruction is more than twice as big > as D=D+R1 or D=D< 0 is faster than --n >= 0. Especially when n is unsigned... -- GPG: D5D4E405 - 2F9B BCCC 8527 692A 04E3 331E FAF8 226A D5D4 E405 _______________________________________________ Guile-user mailing list Guile-user@gnu.org http://mail.gnu.org/mailman/listinfo/guile-user