From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752404Ab3KKCXP (ORCPT ); Sun, 10 Nov 2013 21:23:15 -0500 Received: from smtprelay0141.hostedemail.com ([216.40.44.141]:52166 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751061Ab3KKCWv (ORCPT ); Sun, 10 Nov 2013 21:22:51 -0500 X-Session-Marker: 6A6F6540706572636865732E636F6D X-Spam-Summary: 2,0,0,,d41d8cd98f00b204,joe@perches.com,:::::::::::::::::,RULES_HIT:41:355:379:541:599:988:989:1260:1261:1277:1311:1313:1314:1345:1359:1373:1437:1515:1516:1518:1534:1540:1593:1594:1711:1730:1747:1777:1792:1981:2194:2199:2393:2559:2562:2693:2828:3138:3139:3140:3141:3142:3352:3622:3865:3867:3868:3870:3871:3872:3874:4321:5007:7652:9108:10004:10400:10848:11232:11658:11914:12517:12519:12740:13069:13311:13357,0,RBL:none,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fn,MSBL:0,DNSBL:none,Custom_rules:0:0:0 X-HE-Tag: blow29_52b3de8c9fd09 X-Filterd-Recvd-Size: 2121 Message-ID: <1384136570.4771.5.camel@joe-AO722> Subject: Re: [tip:x86/asm] x86, bitops: Change bitops to be native operand size From: Joe Perches To: "H. Peter Anvin" Cc: linux-arch , mingo@kernel.org, linux-kernel@vger.kernel.org, tglx@linutronix.de, james.t.kukunas@intel.com, hpa@linux.intel.com, Linus Torvalds , David Miller Date: Sun, 10 Nov 2013 18:22:50 -0800 In-Reply-To: <52803BA2.2080908@zytor.com> References: <1384117768.3081.10.camel@joe-AO722> <5ac67859-a0b2-47f5-bdc2-c2a52b8d6885@email.android.com> <1384123457.3081.33.camel@joe-AO722> <52803BA2.2080908@zytor.com> Content-Type: text/plain; charset="ISO-8859-1" X-Mailer: Evolution 3.8.4-0ubuntu1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 2013-11-10 at 18:06 -0800, H. Peter Anvin wrote: > On 11/10/2013 02:44 PM, Joe Perches wrote: > > On Sun, 2013-11-10 at 14:10 -0800, H. Peter Anvin wrote: > >> Yes, on the generic it is int. > >> The problem is in part that some architectures have bitop > >> instructions with specific behavior. > > I think that all bitop indices should be changed > > to unsigned (int or long, probably long) for all > > arches. > > Is there any impediment to that? > It is at the very best misleading. On x86 bit indicies will be signed > no matter what the data type says, ? > and having an unsigned data type > being interpreted as signed seems like really dangerous. > On the other hand, for the generic implementation unsigned long makes sense. > We might need a bitindex_t or something like that for it to be clean. Is there really any reason to introduce bitindex_t? Perhaps the current x86 bitops asm code is being conflated with the ideal implementation?