From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-x22d.google.com (mail-wm0-x22d.google.com [IPv6:2a00:1450:400c:c09::22d]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 5A2321A1E01 for ; Tue, 30 Aug 2016 04:08:43 -0700 (PDT) Received: by mail-wm0-x22d.google.com with SMTP id o80so29526124wme.1 for ; Tue, 30 Aug 2016 04:08:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=WchH5Fsw51WMIlzO3nUjXDDxai21XDJBLKob/EO06fc=; b=Koin+xNOQ4i3n/SkjNqxat3ASer6r7hJtv3MfM4t1qjk66F8VfcYExyDqTat+a1Se8 gQlc542YNkI9HcQPVWgQu2G+ASWeaQFk0MTbrl4j/Fgn6C9OQqcKcx1YPlj+nHT+YjGU fO+deQWbj24Fv0UXGxuBnLW7YD8oXvc90J9RnJ3t4HW3/eopir+UF54vDpb29eCiHS37 wioAfWj38nmaLkW6HNP36z1dZ8v7RufF7l9gBSa+UTpNNnHvltr79v00U/0Ty6nWT4uh cniVTpNxm3ykCwz59gw/n3ICOhR7Vnx83ouBY7rvTNw5LVQfZJZHf7885BldEPM3F5Ip ME8A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=WchH5Fsw51WMIlzO3nUjXDDxai21XDJBLKob/EO06fc=; b=YGyrH2WrbV+xqf71b99tPYFMypRsaitc+L5CsrvKzampIxa75/3obovAC02E41ClNS 3eiYhjzhn9tM5J9Wr5TLozVGoSHa8zBFhxSuD+frQf4o9NAF68tKRr6+9LrPe7AzK1VB OeDqUHnDFu5lLz7/CoGkzBOrGI2zRbsOCkzp5e/lFXC6+1nm5VdsJAUigk93Pycu58L/ mFGdTNZqtvxixmLVXzS6k0VG7I2hPJJf7I+lda7vH3/KEpR+IbFIZpRWVtscI/k5agtW Pf1W687ndHPUl/+TT0Zokf9yUxH1u1SAqh1HHoBnkNaAOUIgqvNoTfHc52Nemkx+1sXi n2ug== X-Gm-Message-State: AE9vXwNNTsY2H3qS7/o8AhUPHs/WP02pQpaaRGYgQC3PeTcYRmelS8uPh6VYMVS0Qmm7kqNlXAS8rZMesKXwpA== X-Received: by 10.28.140.5 with SMTP id o5mr3423080wmd.13.1472555321658; Tue, 30 Aug 2016 04:08:41 -0700 (PDT) MIME-Version: 1.0 Received: by 10.28.238.198 with HTTP; Tue, 30 Aug 2016 04:08:41 -0700 (PDT) In-Reply-To: References: From: Michael Zimmermann Date: Tue, 30 Aug 2016 13:08:41 +0200 Message-ID: To: valerij zaporogeci Cc: edk2-devel X-Content-Filtered-By: Mailman/MimeDel 2.1.21 Subject: Re: Crc32 X-BeenThere: edk2-devel@lists.01.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: EDK II Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 30 Aug 2016 11:08:43 -0000 Content-Type: text/plain; charset=UTF-8 well as u already said, the spec says it uses 'a standard CCITT32 CRC algorithm with a seed polynomial value of 0x04c11db7' this is the implementation which confirms it: https://github.com/tianocore/edk2/blob/master/MdeModulePkg/Core/RuntimeDxe/Crc32.c after testing it it indeed produces CCITT32 results like this online generator: http://g6auc.me.uk/CRC32/index.html Thanks Michael On Tue, Aug 30, 2016 at 2:54 AM, valerij zaporogeci wrote: > Hi, all. > Yet another dumb question from me. > UEFI specification has Crc32 calculation service and uses Crc32 in > several places. but it only humbly mentions in the note somewhere in > the description of System Table about what exact one it wants. Namely > it states that the polynomial seed is 04c11db7. And that's all. > My question is - does really the specification means the 33-bit polynomial > 104c11db7? And is the algorithm just a plain remainder calculation > without any additional pre/post processing of it? So that for example > Crc32 of the 4-byte sequence b16b00b5 would be > 8c1f0a7c? > Thank you. > _______________________________________________ > edk2-devel mailing list > edk2-devel@lists.01.org > https://lists.01.org/mailman/listinfo/edk2-devel >