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,MAILING_LIST_MULTI autolearn=ham autolearn_force=no version=3.4.4 Received: (qmail 23106 invoked from network); 19 Sep 2023 00:03:05 -0000 Received: from minnie.tuhs.org (50.116.15.146) by inbox.vuxu.org with ESMTPUTF8; 19 Sep 2023 00:03:05 -0000 Received: from minnie.tuhs.org (localhost [IPv6:::1]) by minnie.tuhs.org (Postfix) with ESMTP id 903D24029B; Tue, 19 Sep 2023 10:03:00 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=tuhs.org; s=dkim; t=1695081780; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:list-id:list-help: list-owner:list-unsubscribe:list-subscribe:list-post; bh=6zd/FNRt2cRc4hyTAQZTZEJo8C3M436Hw9WOWX8W0Qk=; b=RcImy4TV4IP3kRfkmaobYTOscRD2gxDf67JowK7upeiB1hyHOmIBvBErsMRquPFCfKKIJU +BHc48gT3UVSxfSJMZoTQP55Rv+qOe7p0od0XlCNpSkfM+JYZKwZ6G/JL/2DCoFSTAJPob IZFCwvWwXw/eMieJfNsOcoXlLVvhfWY= Received: from mail-40138.protonmail.ch (mail-40138.protonmail.ch [185.70.40.138]) by minnie.tuhs.org (Postfix) with ESMTPS id 723FF4029A for ; Tue, 19 Sep 2023 10:02:56 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=protonmail.com; s=protonmail3; t=1695081774; x=1695340974; bh=6zd/FNRt2cRc4hyTAQZTZEJo8C3M436Hw9WOWX8W0Qk=; h=Date:To:From:Subject:Message-ID:In-Reply-To:References: Feedback-ID:From:To:Cc:Date:Subject:Reply-To:Feedback-ID: Message-ID:BIMI-Selector; b=AA6/VoR6M7iscrSnS12/TyTEiji2onV4OViukrQcfM9C4I7BdH+ggyQZNHt75m8k5 QUud5ycsJAnt/d6pXI2IuEtF5lvV/OsJUiMtvWxkm1lqpplK6b1tS/2IxnUW36ZKZ2 oNOHGAeQvI+cad45jTKCg92DdLFC6zZqG+zc9QtAwlYbVDW5aXDF8MB1awQdtg8wjH xDNHp5j6s0KE6KCBF+IagV18r/N8JqNGRQWhVeFbeAVa7IO81DbbDcf9men5CImvfU pJmxTgLfn0gCIksnv5syM41POLbmtdv72hi4gEd4+wQYYOmPQdLTaxX8o7Ep351//s jCNKiRy0cKhcg== Date: Tue, 19 Sep 2023 00:02:50 +0000 To: The Eunuchs Hysterical Society Message-ID: In-Reply-To: <87246EC9-0AC8-404E-A8DD-508AB046018B@planet.nl> References: <87246EC9-0AC8-404E-A8DD-508AB046018B@planet.nl> Feedback-ID: 35591162:user:proton MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Message-ID-Hash: COWDR2MXOY64ZFIXX5TIMPRGLMJCRKKF X-Message-ID-Hash: COWDR2MXOY64ZFIXX5TIMPRGLMJCRKKF X-MailFrom: segaloco@protonmail.com X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; 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: CRC calculation in the 1980s List-Id: The Unix Heritage Society mailing list Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: From: segaloco via TUHS Reply-To: segaloco > Any suggestions as to why the on-the-fly algorithm did not catch on more = in the 1980=E2=80=99s? Maybe it was simply less well known than I think? The CRC algorithm I'm familiar with shows up in Dragon Quest for the Famico= m in 1986[1], written in 6502 assembly. Admittedly though I only recognize= d it due to the EOR with 0x1021 on lines 318-323. That I then only know fr= om a quick and dirty CRC I threw in an XMODEM-CRC client [2] I did to accom= modate for a bug in the JH7100 RISC-V board's recovery ROM implementation. = Not sure if this is along the lines of the approach you're talking about, = admittedly these two instances are literally all I know about CRC, just eno= ugh to be dangerous :) Still, a concrete example of ChunSoft's 6502 CRC calculation in the mid 80s= , if that helps with the assessment of the time period/flow of ideas in the= industry. - Matt G. [1] - https://gitlab.com/segaloco/dq1disasm/-/blob/master/src/chr3/start_pw= .s [2] - https://gitlab.com/segaloco/riscv-bits/-/blob/master/util/sxj.c