Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752836Ab1CUFfh (ORCPT ); Mon, 21 Mar 2011 01:35:37 -0400 Received: from mail-iw0-f174.google.com ([209.85.214.174]:34577 "EHLO mail-iw0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752720Ab1CUFfg convert rfc822-to-8bit (ORCPT ); Mon, 21 Mar 2011 01:35:36 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=f2+Fl/58c5DJP/jDk4nw6QlfJnY6GnVlpc2aGNootgnXLgAXsM5yrMjhvsLOObUDDV ByzzG1sJbXsdxjWVQasBmDOo83HcdzfWcvUGOUGy8tPXkElaTtW9CYa7XZmJo3LTy9p/ Hl+1JvgR4seDKRiD0w8yHCKmtvdhKw/OAAq50= MIME-Version: 1.0 In-Reply-To: <201103210108.49780.vapier@gentoo.org> References: <201103162257.10440.vapier@gentoo.org> <201103210108.49780.vapier@gentoo.org> Date: Sun, 20 Mar 2011 22:35:35 -0700 Message-ID: Subject: Re: X32 psABI status update From: "H.J. Lu" To: Mike Frysinger Cc: libc-alpha@sourceware.org, GCC Development , LKML , x32-abi@googlegroups.com Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2017 Lines: 45 On Sun, Mar 20, 2011 at 10:08 PM, Mike Frysinger wrote: > On Thursday, March 17, 2011 01:21:16 H.J. Lu wrote: >> On Wed, Mar 16, 2011 at 7:57 PM, Mike Frysinger wrote: >> > in looking at the gcc files, it doesnt seem like there's any defines >> > setup to declare x32 directly. ?instead, you'd have to do something >> > like: #ifdef __x86_64__ >> > # if __SIZEOF_LONG__ == 8 >> > /* x86_64 */ >> > # else >> > /* x32 */ >> > # endif >> > #endif >> > >> > any plans on adding an __x32__ (or whatever) cpp symbol to keep people >> > from coming up with their own special/broken crap ? ?or are there some >> > already that i'm not seeing ? >> >> The idea is in most cases, you only need to check __x86_64__ since x32 and >> x86-64 are very close. ?In some cases, x32 is very different from x86_64, >> like assembly codes on long and pointer, you can check __x86_64__ and >> __LP64__. In glibc, I used a different approach by using macros REG_RAX, >> .., MOV_LP, ADD_LP, SUB_LP and CMP_LP in assembly codes. > > while i agree with you in general that this is how people should be doing > things, in practice i often see people fishing around. ?education only goes so > far, so if there was an __x32__ define, i feel like people are more likely to > get it right than wrong. > > i dont have any use cases off the top of my head, but i wouldnt be surprised > if the heavy inline assembly people (like the multimedia peeps e.g. libav) > approached it this way. ?rather than google for documentation, look at the cpp > output between -m64 and -mx32 and see what sticks out. ?"__x32__" would > certainly do that. My point is __x86_64__ version should work for both 64bit and x32. There should no need for a separate x32 version. -- H.J. -- 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/