From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=5.0 tests=MAILING_LIST_MULTI autolearn=ham autolearn_force=no version=3.4.4 Received: (qmail 6896 invoked from network); 25 Oct 2022 22:49:06 -0000 Received: from minnie.tuhs.org (50.116.15.146) by inbox.vuxu.org with ESMTPUTF8; 25 Oct 2022 22:49:06 -0000 Received: from minnie.tuhs.org (localhost [IPv6:::1]) by minnie.tuhs.org (Postfix) with ESMTP id 9EE5641DBB; Wed, 26 Oct 2022 08:48:42 +1000 (AEST) Received: from fuz.su (fuz.su [5.135.162.8]) by minnie.tuhs.org (Postfix) with ESMTPS id 16BE341DB9 for ; Wed, 26 Oct 2022 08:48:37 +1000 (AEST) Received: from fuz.su (localhost [127.0.0.1]) by fuz.su (8.16.1/8.16.1) with ESMTPS id 29PMlKhE006139 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO) for ; Tue, 25 Oct 2022 22:47:20 GMT (envelope-from fuz@fuz.su) Received: (from fuz@localhost) by fuz.su (8.16.1/8.16.1/Submit) id 29PMlKdj006138 for tuhs@tuhs.org; Wed, 26 Oct 2022 00:47:20 +0200 (CEST) (envelope-from fuz) Date: Wed, 26 Oct 2022 00:47:20 +0200 From: Robert Clausecker To: The Eunuchs Hysterical Society Message-ID: References: <6848E086-1F60-4476-A228-AB3A158EC8CB@iitbombay.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <6848E086-1F60-4476-A228-AB3A158EC8CB@iitbombay.org> Message-ID-Hash: O6YHZFM6JINHGRLWUZRARVYM67N2MPLL X-Message-ID-Hash: O6YHZFM6JINHGRLWUZRARVYM67N2MPLL X-MailFrom: fuz@fuz.su X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; header-match-tuhs.tuhs.org-0; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header X-Mailman-Version: 3.3.6b1 Precedence: list Subject: [TUHS] Re: who invented the link register List-Id: The Unix Heritage Society mailing list Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: Am Tue, Oct 25, 2022 at 03:24:01PM -0700 schrieb Bakul Shah: > On Oct 12, 2022, at 12:01 PM, ron minnich wrote: > > > > I know branch and link was in the 360; was it earlier? And ... anybody > > know who invented it? > > > > This came up in a risc-v meeting just now :-) My claim is that if anybody > > knows, they will be in this group. > > Zuse Z4 had instructions to jump to a subprogram and back. Unclear if > they were in the original Z4 (1945) or were added later. Or how it was done. The Z4's programs were stored on a number of tapes. Initially, there was only one tape reader and no branch instructions. Later, the design was modified by adding additional tape readers and instructions to switch to a different tape reader. Thus, sub programs can be realised by storing the subprogram on a different, possibly looped, tape and then switching to the other tape reader when the sub program is called. The subprogram's final instruction would switch back to the main tape reader. So not quite a link register. An instruction set reference for a later (1950) model can be found in the ETH Zurich library: https://www.e-manuscripta.ch/zut/doi/10.7891/e-manuscripta-98601 Yours, Robert Clausecker -- () ascii ribbon campaign - for an 8-bit clean world /\ - against html email - against proprietary attachments