From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Emanuel Berg Newsgroups: gmane.emacs.devel Subject: Re: [PATCH] Re: Bignum performance Date: Wed, 16 Aug 2023 00:46:03 +0200 Message-ID: <87h6ozgc0k.fsf@dataswamp.org> References: <87bkfartof.fsf@localhost> <175cf474-29c8-a482-072e-0de784ac59e8@gmail.com> <87o7jaqc31.fsf@localhost> <2d419e12-9239-de3e-47d0-38815a00025f@gmail.com> <87msyth8jh.fsf@dataswamp.org> <871qg4n7n4.fsf@yahoo.com> <87wmxwfk9r.fsf@dataswamp.org> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="33546"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) To: emacs-devel@gnu.org Cancel-Lock: sha1:yk+qv6vk83AQzWpWxD/bbF0Jmt4= Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Wed Aug 16 04:21:53 2023 Return-path: Envelope-to: ged-emacs-devel@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1qW6AT-0008VV-Nc for ged-emacs-devel@m.gmane-mx.org; Wed, 16 Aug 2023 04:21:53 +0200 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qW69W-0007HT-In; Tue, 15 Aug 2023 22:20:54 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qW2no-0006T7-Fb for emacs-devel@gnu.org; Tue, 15 Aug 2023 18:46:16 -0400 Original-Received: from ciao.gmane.io ([116.202.254.214]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qW2nl-000878-P7 for emacs-devel@gnu.org; Tue, 15 Aug 2023 18:46:16 -0400 Original-Received: from list by ciao.gmane.io with local (Exim 4.92) (envelope-from ) id 1qW2nj-0001Hm-CX for emacs-devel@gnu.org; Wed, 16 Aug 2023 00:46:11 +0200 X-Injected-Via-Gmane: http://gmane.org/ Mail-Followup-To: emacs-devel@gnu.org Mail-Copies-To: never Received-SPF: pass client-ip=116.202.254.214; envelope-from=ged-emacs-devel@m.gmane-mx.org; helo=ciao.gmane.io X-Spam_score_int: -15 X-Spam_score: -1.6 X-Spam_bar: - X-Spam_report: (-1.6 / 5.0 requ) BAYES_00=-1.9, HEADER_FROM_DIFFERENT_DOMAINS=0.25, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-Mailman-Approved-At: Tue, 15 Aug 2023 22:20:53 -0400 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Xref: news.gmane.io gmane.emacs.devel:308783 Archived-At: tomas wrote: >>>> Are we talking 1 word = 2 bytes = 16 bits here, s2c? >>>> >>>> If so, the range of fixnums are -32 768 to 32 767 >>>> inclusive, so those are hardly huge numbers. >>> >>> Under Arm64, general purpose integer registers are 64 bits >>> wide. That is also the word size of said machine. >> >> If they are, the range for fixnums is >> >> (list (* -1 (expt 2 (1- 64))) >> (1- (expt 2 (1- 64))) ) >> >> (-9223372036854775808 9223372036854775807) >> >> Only after that it gets slower :P > > Unless SBCL uses tagged object representation. Unless the > compiler can prove that some "thing" is going to be an int. > Unless... Actually the rules are quite simple. As long as the expected execution and correct return value is observed and ultimately achieved by the algorithm, all optimizations are fair. -- underground experts united https://dataswamp.org/~incal