Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932289AbVIYUzi (ORCPT ); Sun, 25 Sep 2005 16:55:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932290AbVIYUzi (ORCPT ); Sun, 25 Sep 2005 16:55:38 -0400 Received: from styx.suse.cz ([82.119.242.94]:63700 "EHLO mail.suse.cz") by vger.kernel.org with ESMTP id S932289AbVIYUzh (ORCPT ); Sun, 25 Sep 2005 16:55:37 -0400 Date: Sun, 25 Sep 2005 22:54:55 +0200 From: Vojtech Pavlik To: Denis Vlasenko Cc: Grant Coady , Simon Evans , linux-kernel@vger.kernel.org Subject: Re: New inventions in rounding up in catc.c? Message-ID: <20050925205455.GA6747@midnight.ucw.cz> References: <200509241343.42464.vda@ilport.com.ua> <200509251343.47892.vda@ilport.com.ua> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200509251343.47892.vda@ilport.com.ua> X-Bounce-Cookie: It's a lemon tree, dear Watson! User-Agent: Mutt/1.5.10i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1136 Lines: 32 On Sun, Sep 25, 2005 at 01:43:47PM +0300, Denis Vlasenko wrote: > On Saturday 24 September 2005 21:46, Grant Coady wrote: > > On Sat, 24 Sep 2005 13:43:42 +0300, Denis Vlasenko wrote: > > > /* F5U011 only does one packet per RX */ > > > if (catc->is_f5u011) > > > break; > > >- pkt_start += (((pkt_len + 1) >> 6) + 1) << 6; > > >+ pkt_start += ((pkt_len + 2) + 63) & ~63; > > > > pkt_start += ((pkt_len + 1) + 64) & ~63; > > > > Seems more clear to me. > > Why? > > ((pkt_len + 2) + 63) & ~63 is "add 2 and round up to next 64". > ((pkt_len + 1) + 64) & ~63 is "???!" > > It's strange code anyway, I hope maintainer can clarify what's going on. > (I suspect it was intended to be pkt_len - 1, not +, in the first place) Honestly, I don't remember at all. I'll try to find the (very old) docs I have for the chip. -- Vojtech Pavlik SuSE Labs, SuSE CR - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/