From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.bugs Subject: bug#32605: [w64] (random) never returns negative Date: Sat, 14 Aug 2021 15:36:09 +0300 Message-ID: <834kbsb3uu.fsf@gnu.org> References: <855zzpf86u.fsf@gmail.com> <87zhx1ktp0.fsf@gmx.net> <87zhwwhp9i.fsf@gmail.com> <87mtpmls3p.fsf_-_@gnus.org> <83o8a2dbjo.fsf@gnu.org> <86bl62s8qm.fsf@gmail.com> <83czqhdfhm.fsf@gnu.org> <861r6xoxqa.fsf@gmail.com> <83sfzcbmfm.fsf@gnu.org> <86mtpksa0l.fsf@gmail.com> <83a6lkbe02.fsf@gnu.org> <86sfzcjnfr.fsf@gmail.com> <835yw8b6s3.fsf@gnu.org> <86fsvcz0pr.fsf@gmail.com> Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="10638"; mail-complaints-to="usenet@ciao.gmane.io" Cc: 32605@debbugs.gnu.org To: Andy Moreton Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Sat Aug 14 14:37:10 2021 Return-path: Envelope-to: geb-bug-gnu-emacs@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 1mEsuU-0002fd-6Y for geb-bug-gnu-emacs@m.gmane-mx.org; Sat, 14 Aug 2021 14:37:10 +0200 Original-Received: from localhost ([::1]:56536 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mEsuS-0006Jj-6A for geb-bug-gnu-emacs@m.gmane-mx.org; Sat, 14 Aug 2021 08:37:08 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:57240) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mEsuM-0006JU-AV for bug-gnu-emacs@gnu.org; Sat, 14 Aug 2021 08:37:02 -0400 Original-Received: from debbugs.gnu.org ([209.51.188.43]:60477) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1mEsuM-0004Mk-3L for bug-gnu-emacs@gnu.org; Sat, 14 Aug 2021 08:37:02 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1mEsuL-00064e-Rc for bug-gnu-emacs@gnu.org; Sat, 14 Aug 2021 08:37:01 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Eli Zaretskii Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Sat, 14 Aug 2021 12:37:01 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 32605 X-GNU-PR-Package: emacs X-GNU-PR-Keywords: confirmed Original-Received: via spool by 32605-submit@debbugs.gnu.org id=B32605.162894459123311 (code B ref 32605); Sat, 14 Aug 2021 12:37:01 +0000 Original-Received: (at 32605) by debbugs.gnu.org; 14 Aug 2021 12:36:31 +0000 Original-Received: from localhost ([127.0.0.1]:43789 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1mEstr-00063v-IR for submit@debbugs.gnu.org; Sat, 14 Aug 2021 08:36:31 -0400 Original-Received: from eggs.gnu.org ([209.51.188.92]:40734) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1mEsto-00063e-Dt for 32605@debbugs.gnu.org; Sat, 14 Aug 2021 08:36:29 -0400 Original-Received: from fencepost.gnu.org ([2001:470:142:3::e]:49452) by eggs.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mEsti-00047x-HM; Sat, 14 Aug 2021 08:36:23 -0400 Original-Received: from 84.94.185.95.cable.012.net.il ([84.94.185.95]:2943 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mEsti-0006SC-3E; Sat, 14 Aug 2021 08:36:22 -0400 In-Reply-To: <86fsvcz0pr.fsf@gmail.com> (message from Andy Moreton on Sat, 14 Aug 2021 13:10:08 +0100) X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list X-BeenThere: bug-gnu-emacs@gnu.org List-Id: "Bug reports for GNU Emacs, the Swiss army knife of text editors" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Original-Sender: "bug-gnu-emacs" Xref: news.gmane.io gmane.emacs.bugs:211830 Archived-At: > From: Andy Moreton > Date: Sat, 14 Aug 2021 13:10:08 +0100 > > > Why not keep the 30 bits we produce today on 32-bit builds? > > For 32bit builds (FIXNUM_BITS is 30), either: > > a) define RAND_BITS to 30, 'random' calls 'rand_as183' twice. > 'get_random' needs 1 call to 'random' (total 2 calls of 'rand_as183'). > > b) define RAND_BITS to 15, 'random' calls 'rand_as183' once. > 'get_random' needs 2 calls to 'random' (total 2 calls of 'rand_as183'). > > For 64bit builds (FIXNUM_BITS is 62), either: > > a) define RAND_BITS to 30, 'random' calls 'rand_as183' twice. > 'get_random' needs 3 calls to 'random' (total 6 calls of 'rand_as183'). > > b) define RAND_BITS to 15, 'random' calls 'rand_as183' once. > 'get_random' needs 4 calls to 'random' (total 4 calls of 'rand_as183'). > > On 32bit builds both options are roughly equivalent. > On 64bit builds option (b) is better as option (a) does unnecessary work. The above assumes we will never call 'random' except via 'get_random'. Is that something we want to bet on?