Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264152AbTKTG6E (ORCPT ); Thu, 20 Nov 2003 01:58:04 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264283AbTKTG6E (ORCPT ); Thu, 20 Nov 2003 01:58:04 -0500 Received: from dslb138.fsr.net ([12.7.7.138]:60802 "EHLO sandall.us") by vger.kernel.org with ESMTP id S264152AbTKTG57 (ORCPT ); Thu, 20 Nov 2003 01:57:59 -0500 Message-ID: <1069311476.3fbc65f46135c@horde.sandall.us> Date: Wed, 19 Nov 2003 22:57:56 -0800 From: Eric Sandall To: Ben Collins Cc: Nico Schottelius , linux-kernel@vger.kernel.org Subject: Re: transmeta cpu code question References: <20031120020218.GJ3748@schottelius.org> <20031120025315.GR11983@phunnypharm.org> In-Reply-To: <20031120025315.GR11983@phunnypharm.org> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT User-Agent: Internet Messaging Program (IMP) 3.2.2 X-Originating-IP: 192.168.0.2 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2125 Lines: 64 Quoting Ben Collins : > On Thu, Nov 20, 2003 at 03:02:18AM +0100, Nico Schottelius wrote: > > Hello! > > > > What does this do: > > > > printk(KERN_INFO "CPU: Processor revision %u.%u.%u.%u, > > %u MHz\n", > > (cpu_rev >> 24) & 0xff, > > (cpu_rev >> 16) & 0xff, > > (cpu_rev >> 8) & 0xff, > > cpu_rev & 0xff, > > cpu_freq); > > > > (from arch/i386/kernel/cpu/transmeta.c) > > > > Does not & 0xff make no sense? 0 & 1 makes 0, 1 & 1 makes 1, > > no changes. > > > > And I don't understand why we do this for 8bit and shifting the > > cpu_rev... > > You are a bit confused. The cpu_rev is a 4 byte value, each byte is a > decimal of the revision. > > And (0 & 1) makes 1, not 0. That's an AND, not an OR. Last I checked, 0 AND anything is 0. Think of it this way: A B A & B ------------ T F F T T T F T F F F F So, anything ANDed with F is false. -sandalle -- PGP Key Fingerprint: FCFF 26A1 BE21 08F4 BB91 FAED 1D7B 7D74 A8EF DD61 http://search.keyserver.net:11371/pks/lookup?op=get&search=0xA8EFDD61 -----BEGIN GEEK CODE BLOCK----- Version: 3.12 GCS/E/IT$ d-- s++:+>: a-- C++(+++) BL++++VIS>$ P+(++) L+++ E-(---) W++ N+@ o? K? w++++>-- O M-@ V-- PS+(+++) PE(-) Y++(+) PGP++(+) t+() 5++ X(+) R+(++) tv(--)b++(+++) DI+@ D++(+++) G>+++ e>+++ h---(++) r++ y+ ------END GEEK CODE BLOCK------ Eric Sandall | Source Mage GNU/Linux Developer eric@sandall.us | http://www.sourcemage.org/ http://eric.sandall.us/ | SysAdmin @ Inst. Shock Physics @ WSU http://counter.li.org/ #196285 | http://www.shock.wsu.edu/ ---------------------------------------------------------------- This message was sent using IMP, the Internet Messaging Program. - 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/