From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-1.1 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,HTML_MESSAGE, MAILING_LIST_MULTI autolearn=ham autolearn_force=no version=3.4.4 Received: from minnie.tuhs.org (minnie.tuhs.org [IPv6:2600:3c01:e000:146::1]) by inbox.vuxu.org (Postfix) with ESMTP id DC30029459 for ; Wed, 10 Jul 2024 04:21:23 +0200 (CEST) Received: from minnie.tuhs.org (localhost [IPv6:::1]) by minnie.tuhs.org (Postfix) with ESMTP id 501074287D; Wed, 10 Jul 2024 12:21:17 +1000 (AEST) Received: from mail-ua1-x930.google.com (mail-ua1-x930.google.com [IPv6:2607:f8b0:4864:20::930]) by minnie.tuhs.org (Postfix) with ESMTPS id 1EF1742867 for ; Wed, 10 Jul 2024 12:21:10 +1000 (AEST) Received: by mail-ua1-x930.google.com with SMTP id a1e0cc1a2514c-81177442f46so51890241.3 for ; Tue, 09 Jul 2024 19:21:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=dartmouth.edu; s=google1; t=1720578069; x=1721182869; darn=tuhs.org; h=to:subject:message-id:date:from:mime-version:from:to:cc:subject :date:message-id:reply-to; bh=6FdKh7cK5O2pUmaaT7aatK5FJvOSLdWOPuT5hQtA4j8=; b=kYHMC4QpRVWgGKSEI5Rs4c05qF0kqayFc6oqntpAkH01cpBQ8LtWa5tWe+5WZv+1S+ 9DHX8pnWr8Kf205usCXF+ERMO8MxZy8ULOEJouXVJbvTxmmyf787xJOi+9ztmRInkTGg QkSwL4BTado6clp0R9dB+pysTRouTJ027a++m8+XSLJgbgtz34RiD+wJIp0OBTF3Z07v JTlQNp5iOCZBjqmJrBZV2/ketFKfA5b0xiWyzwy+JY0N2Xo5PrsnfK4GNDseS0eJkZkL 7/lsH8apt5aNBfwwcrdpIGZh5EqsQC9pOHl9GHEFXxTvxfZ98a9Fg4xtPq1QRh3iJiDV ydaw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1720578069; x=1721182869; h=to:subject:message-id:date:from:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=6FdKh7cK5O2pUmaaT7aatK5FJvOSLdWOPuT5hQtA4j8=; b=oetrxidtkN5e3kqm3UIr4LLBsj1GnK1KV9r/JQHM4TcPv3msJICy5ynm0mCfXQR+S8 enG3VSvCwCTrv/jw/2rfTKUC2yyxQhluBgSgiHv19e+vUsVNSFBQLYaBqgazbcV97E2H QL/ZE2c+Ga3D0F5aEEupIWco1vf+Q/H+huhYWaeUq2+GjTEbMYrE4809fP9OQjE2F2ls nTnF4S3ZQNM1m167U7w+Soy2WYbkvx2J1mMg0UHmcgjGQ6LmAora4xyf3S6cNAA2GAHK pOf42rmZImw8owopX/kmRzSBgdtdYPVH/9XwvxFvhNvDAsH2maj+Wdxqggaa0+jeDzbW vTjw== X-Gm-Message-State: AOJu0YxeUAOABNCy3pP64F1j5faLSB6GxmdW+IvBcMaSPQf6d10/8z1A jzSXgfPM1jon+G8KNQSohBggoNb59M28u90HoBinx1JtpxkUSJ38lleYohVkUbFkCmvhtqBHNvL lClkHBvn7ZPQICdSU9OTjguUqgED345zAtFKaq5MGBZaMpOcOUJY= X-Google-Smtp-Source: AGHT+IGYZeMSUXLoJqItTCVkvoExasT1yjafPQ/DfqDkM8B7FGApKGK5OsT/vZdAuFsKXHcCOk95UadTf0GveJMdQR8= X-Received: by 2002:a05:6102:2ad6:b0:48f:c0ee:28e8 with SMTP id ada2fe7eead31-490321b898emr4538039137.16.1720578068904; Tue, 09 Jul 2024 19:21:08 -0700 (PDT) MIME-Version: 1.0 From: Douglas McIlroy Date: Tue, 9 Jul 2024 22:20:54 -0400 Message-ID: To: TUHS main list Content-Type: multipart/alternative; boundary="0000000000009b1bc4061cdb4ce2" Message-ID-Hash: 7CLTFT4DGUTQI65YK2Q724KI4BFFXCBN X-Message-ID-Hash: 7CLTFT4DGUTQI65YK2Q724KI4BFFXCBN X-MailFrom: douglas.mcilroy@dartmouth.edu 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: mental architecture models, Anyone ever heard of teaching a case study of Initial Unix? List-Id: The Unix Heritage Society mailing list Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: --0000000000009b1bc4061cdb4ce2 Content-Type: text/plain; charset="UTF-8" > In order to port VMS to new architectures, DEC/HP/VSI ... > turned the VAX MACRO assembly language (in which > some of the VMS operating system was written) into a > portable implementation language by 'compiling' the > high-level CISC VAX instructions (and addressing modes) > into sequences of RISC instructions. Clem Pease did the same thing to port TMG from IBM 7000-series machines to the GE 600 series for Multics, circa 1967. Although both architectures had 36-bit words, it was a challenge to adequately emulate IBM's accumulator, which supported 38-bit sign-magnitude addition, 37-bit twos-complement and 36-bit ones-complement. Doug --0000000000009b1bc4061cdb4ce2 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
> In order to port VMS to ne= w architectures, DEC/HP/VSI ...=C2=A0
> turned the= VAX MACRO assembly language (in which=C2=A0
> som= e of the VMS operating system was written) into a
> portable implemen= tation language by 'compiling' the=C2=A0
>= high-level CISC VAX instructions (and addressing modes)=C2=A0
> into sequences of RISC instructions.=C2=A0

Clem Pease did the same thing to port TMG from IBM 7000= -series machines to the GE=C2=A0 600 series for Multics, circa 1967. Althou= gh both architectures had 36-bit words, it was a challenge to adequately em= ulate IBM's accumulator, which supported 38-bit sign-magnitude addition= , 37-bit twos-complement and 36-bit ones-complement.

Doug
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