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 (was: Shrinking the C core) Date: Tue, 15 Aug 2023 16:20:03 +0200 Message-ID: <87350kgzfw.fsf@dataswamp.org> References: <87msyth8jh.fsf@dataswamp.org> <54195cac-0e60-f458-9a07-c1574168be4b@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="24793"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) To: emacs-devel@gnu.org Cancel-Lock: sha1:mUrOZ5uWp2t8zyQYa7U+keCJqAE= Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Tue Aug 15 16:54:08 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 1qVvQu-0006DR-Hx for ged-emacs-devel@m.gmane-mx.org; Tue, 15 Aug 2023 16:54:08 +0200 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qVvP8-0006Ji-UG; Tue, 15 Aug 2023 10:52:19 -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 1qVuuC-0003kN-QT for emacs-devel@gnu.org; Tue, 15 Aug 2023 10:20:20 -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 1qVuuA-0007dj-Fx for emacs-devel@gnu.org; Tue, 15 Aug 2023 10:20:20 -0400 Original-Received: from list by ciao.gmane.io with local (Exim 4.92) (envelope-from ) id 1qVuu8-0000ui-9D for emacs-devel@gnu.org; Tue, 15 Aug 2023 16:20:16 +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 10:52:17 -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:308758 Archived-At: Gerd Möllmann 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. > > It's a 64-bit machine, more specifically an M1. i.e. arm64. > How you get from there to these 16 bits escapes me. Here [1] it says a word for ARM is 32 bits. So to store zero in a fixnum word it will look like this 00000000 00000000 00000000 00000000 If one bit, the MSB, is used as the sign bit, the interval, inclusive, is (list (* -1 (expt 2 (1- 32))) (1- (expt 2 (1- 32))) ) (-2147483648 2147483647) Okay, now we are talking some pretty big number alltho I have seen even bigger ... [1] https://modexp.wordpress.com/2018/10/30/arm64-assembly/ -- underground experts united https://dataswamp.org/~incal