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=-1.1 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HTML_MESSAGE,MAILING_LIST_MULTI,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.4 Received: (qmail 25676 invoked from network); 14 Mar 2022 18:03:00 -0000 Received: from minnie.tuhs.org (45.79.103.53) by inbox.vuxu.org with ESMTPUTF8; 14 Mar 2022 18:03:00 -0000 Received: by minnie.tuhs.org (Postfix, from userid 112) id 193AF9D675; Tue, 15 Mar 2022 04:02:58 +1000 (AEST) Received: from minnie.tuhs.org (localhost [127.0.0.1]) by minnie.tuhs.org (Postfix) with ESMTP id B5EA39D605; Tue, 15 Mar 2022 04:01:01 +1000 (AEST) Authentication-Results: minnie.tuhs.org; dkim=pass (1024-bit key; unprotected) header.d=ccc.com header.i=@ccc.com header.b="mdrOERVo"; dkim-atps=neutral Received: by minnie.tuhs.org (Postfix, from userid 112) id BE3819D605; Tue, 15 Mar 2022 04:00:58 +1000 (AEST) Received: from mail-qt1-f179.google.com (mail-qt1-f179.google.com [209.85.160.179]) by minnie.tuhs.org (Postfix) with ESMTPS id 06DA99D5FB for ; Tue, 15 Mar 2022 04:00:58 +1000 (AEST) Received: by mail-qt1-f179.google.com with SMTP id l15so3477635qtk.8 for ; Mon, 14 Mar 2022 11:00:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ccc.com; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=EPugBkYqZsxh3M4AXNU0aCIko56n4RNa5mTd4OSc2Dg=; b=mdrOERVouwU3oaWgI7SMTFQOvh9iixjy+5QfmwVltJ4wd00DZh9QKRZjlJJ6+X5Z31 +86j69YHj6vjxmUc+bfUKlOZHgG2C+eHD02j/k8ia9Sv9DyEbTVm/HxWEqjYa0Y4CVmh faXtUoyXX1bIZxReBbPUunzy52Crvh2LmEK/Y= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=EPugBkYqZsxh3M4AXNU0aCIko56n4RNa5mTd4OSc2Dg=; b=AufDPz7OJ2ums65sqcExJFnSG+uKbKdpxonKzO7dAP/1jlADlG/Cri4FA8Eu6DGTTt 5ghIonQETIfd7c3hljjlhmTX8tDfkQ46P49cux6oJdBBvR5zQkEYqx8U4Obiba1i8Hbx PltbVGJln45qJAy/zRW115KG2e5TuJK1A1iFmchBzEklwLY0R286sM+0vRrd69tdlZRK D1go9Qjo/l0sJdT3SKmYestvFr3WsFv2twiSwCXG001VQA+bXkYgyzlclNYMG2+d0qRN FU7nDijNbA7TgbKodDbRv9w7z4eGSA0rzlnk8LwIn/glESE41XqWnthTN4/z6aNUhUN/ RePg== X-Gm-Message-State: AOAM532GfrD7RYO2hAkkvTI6OnJsbR4R8EByVEf5QZU3lhsHzzTLFQdq 1c0BMeU3HDrswLTf7PuKA+EUc9KW8S0s/e0doBADHUguHo0= X-Google-Smtp-Source: ABdhPJyNHPGk/gLBT6U9fx+68ztoBZt5ex+ifS6gtn9Ofp22jIOk8N1ZIIUk3cCCD0oFg5yy7lUOSrOTFEILDVnbrSg= X-Received: by 2002:a05:622a:1703:b0:2e1:c663:27aa with SMTP id h3-20020a05622a170300b002e1c66327aamr11568414qtk.112.1647280856757; Mon, 14 Mar 2022 11:00:56 -0700 (PDT) MIME-Version: 1.0 References: <20220314165604.4889918C075@mercury.lcs.mit.edu> In-Reply-To: <20220314165604.4889918C075@mercury.lcs.mit.edu> From: Clem Cole Date: Mon, 14 Mar 2022 14:00:32 -0400 Message-ID: To: Noel Chiappa Content-Type: multipart/alternative; boundary="000000000000500f9705da317615" Subject: Re: [TUHS] [tuhs] PDP-11 and early Unix X-BeenThere: tuhs@minnie.tuhs.org X-Mailman-Version: 2.1.26 Precedence: list List-Id: The Unix Heritage Society mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: tuhs@minnie.tuhs.org Errors-To: tuhs-bounces@minnie.tuhs.org Sender: "TUHS" --000000000000500f9705da317615 Content-Type: text/plain; charset="UTF-8" On Mon, Mar 14, 2022 at 12:59 PM Noel Chiappa wrote: > > > Not a bad artcle, but it had a number of minor errors, which I found > irritating. > They should have gotten an expert to proof it. > Sure - but usually these are way more bad than good. Usually way too much urban legend, so I'm thrilled to see the 11 kept alive. > > And a tip of the hatly hat for getting this: > > Although the ++ and - operators in C are equivalents of DEC and INC > instructions, they were inspired by an addressing mode in the PDP-7. > As I said, the authors seem to have done a little homework, although I was under the impression ??Ken?? had created them for B independently (which, of course, was first on the PDP-7). The ++/-- for increment and decrement was just a nice notation since they are such a common occurrence in real code, it's handy to have. But, I did not think the PDP-7 ISA includes addressing modes in the same manner as the 11. I'm probably confused, but I thought PDP-7 is a very simple instruction (and small) with an AC, Link/Indirection and a PC - it reminded me of the PDP-8 more than anything else [although, IIRC it could do both 1's complement and 2's - depending the type of AND instruction]. --000000000000500f9705da317615 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable


On Mon, Mar 14, 2022 at 12:5= 9 PM Noel Chiappa <jnc@mercury.lcs.mit.edu> wrote:
= =C2=A0=C2=A0

Not a bad artcle, but it had a number of minor errors, which I found irrita= ting.
They should have gotten an expert to proof it.
Sure - but usually=C2=A0these are way more bad than good.= =C2=A0 Usually=C2=A0way too much=C2=A0urban legend, so I'm thrilled to = see the 11 kept alive.

And a tip of the hatly hat for getting this:

=C2=A0 Although the ++ and - operators in C are equivalents of DEC and INC<= br> =C2=A0 instructions, they were inspired by an addressing mode in the PDP-7.=
As I said, the authors seem to = have done a little homework, although I was under the impression ??Ken?? ha= d created them for B independently (which, of course, was first on the PDP-= 7).=C2=A0 The ++/-- for increment and decrement was just a nice notation si= nce they are such a common=C2=A0occurrence in real code, it's handy to = have. But, I did not think the PDP-7 ISA includes addressing modes in the s= ame manner as the 11.=C2=A0 I'm probably confused, but I thought PDP-7 = =C2=A0is a very simple instruction (and small) with an AC, Link/Indirection= and a PC - it reminded me of the PDP-8 more than anything else [although, = IIRC it could do both 1's complement and 2's - depending the type o= f AND instruction].
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