From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from emagii.se (www.emagii.com [185.133.207.17]) by sourceware.org (Postfix) with ESMTPS id 634B13858D33 for ; Tue, 28 Feb 2023 13:45:35 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 634B13858D33 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=emagii.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=emagii.com Received: from [10.175.196.145] (84-55-68-216.customers.ownit.se [84.55.68.216]) by emagii.se (Postfix) with ESMTPSA id F048712027F; Tue, 28 Feb 2023 14:45:28 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=emagii.com; s=default; t=1677591934; bh=OnUQTS8oLuLo9W0+ZiFLKGDceHzUr12iuEqVz5ZGVGc=; h=Subject:To:From; b=X0/fXl/g9bOBH7k3TV4KLgb6IlY2svrle2vGSvO+Nr+i6bxC/Wk9OwrHGQkYUwGqE Q78REwSo4Z3MwBdwruI39fICEJqTe6e428zygcJA3TQ9Qw7h5OEGqtCo//iaZw+m8T qd+yT8OUJelw9OHDqOoovKVhVmfxQ5LyT7vDMoeA= Authentication-Results: emagii.beebytevps.io; spf=pass (sender IP is 84.55.68.216) smtp.mailfrom=binutils@emagii.com smtp.helo=[10.175.196.145] Received-SPF: pass (emagii.beebytevps.io: connection is authenticated) Message-ID: <77bce55f-512b-f8d9-83da-24e14e43ab33@emagii.com> Date: Tue, 28 Feb 2023 14:45:28 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.7.1 Subject: Re: [PATCH v4 2/5] CRC64 testsuite Content-Language: en-US To: Nick Clifton , binutils@sourceware.org References: <20230219194549.22554-1-binutils@emagii.com> <20230219194549.22554-3-binutils@emagii.com> <8ebc68e1-25a1-84ef-295f-3e545ced39d0@redhat.com> <1b334d25-10ee-cd05-b2d8-20143ee118a5@emagii.com> <93a59bc2-c62f-c6c5-cee2-fa04ce6907d2@emagii.com> <74421307-88dc-f745-fac0-ba8ae59dcddc@redhat.com> From: Ulf Samuelsson In-Reply-To: <74421307-88dc-f745-fac0-ba8ae59dcddc@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-PPP-Message-ID: <167759193343.3403697.5972596953263162019@localhost.localdomain> X-PPP-Vhost: emagii.com X-Spam-Status: No, score=-4.9 required=5.0 tests=BAYES_00,BODY_8BITS,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,NICE_REPLY_A,SPF_HELO_FAIL,SPF_PASS,TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: On 2023-02-28 13:37, Nick Clifton wrote: > Hi Ulf, > As a matter of interest, where are these names and algorithms defined ? > > Is there a ISO standard for them, for example ? >>   * CRC64-ECMA   ECMA-182 >> https://www.ecma-international.org/publications-and-standards/standards/ecma-182/ >>   * CRC64-ISO       ISO 3309 >>   * CRC64-WE       A variant of ECMA-182, Same polynome but different >> parameters. >>   * CRC64-XZ        A variant of ECMA-182, Same polynome but >> different parameters. >>   * CRC64-POLY    You get to define your own polynome and parameters >>   * CRC32             ISO 3309 >>   * CRC32-POLY    You get to define your own polynome and parameters > Cheers >   Nick > > Here is a good web page explaining CRCs http://www.sunshine2k.de/articles/coding/crc/understanding_crc.html#ch2 There is also an online CRC calculator. http://www.sunshine2k.de/coding/javascript/crc/crc_js.html ======================================== The parameters used are "Size (in bits)" "Polynome" "Initial Value"       CRC is assigned this value in the beginning of the check "Final XOR Value" CRC is XORed with this value before returned "Input Reflected"  Input data is bit reversed before use "Output Reflected" CRC is bitreversed before return (comes before XOR) "Reciprocal"        Polynome is bitreversed  before use All my test uses the string "123456789" as testdata, which is quite common. Best Regards Ulf Samuelsson