From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 12505 invoked by alias); 25 Feb 2015 16:41:03 -0000 Mailing-List: contact libffi-discuss-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libffi-discuss-owner@sourceware.org Received: (qmail 12488 invoked by uid 89); 25 Feb 2015 16:41:03 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.0 required=5.0 tests=AWL,BAYES_00,SPF_HELO_PASS,SPF_PASS,T_RP_MATCHES_RCVD autolearn=ham version=3.3.2 X-HELO: mx1.redhat.com Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES256-GCM-SHA384 encrypted) ESMTPS; Wed, 25 Feb 2015 16:41:02 +0000 Received: from int-mx13.intmail.prod.int.phx2.redhat.com (int-mx13.intmail.prod.int.phx2.redhat.com [10.5.11.26]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id t1PGesNM024140 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Wed, 25 Feb 2015 11:40:54 -0500 Received: from pike.twiddle.home (vpn-62-14.rdu2.redhat.com [10.10.62.14]) by int-mx13.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id t1PGeq66030458; Wed, 25 Feb 2015 11:40:53 -0500 Message-ID: <54EDFB13.60508@redhat.com> Date: Wed, 25 Feb 2015 16:41:00 -0000 From: Richard Henderson User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.4.0 MIME-Version: 1.0 To: "John E. Malmberg" , libffi-discuss@sourceware.org Subject: Re: osf.S using 3 operand jmp and jsr References: In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-IsSubscribed: yes X-SW-Source: 2015/txt/msg00042.txt.bz2 On 02/25/2015 03:18 AM, John E. Malmberg wrote: > I noticed that the src/alpha/osf.S is using 3 operand jmp and jsr instructions. > > What does gas do with the third operand? It encodes it in bits 0:13 as a branch prediction hint. > The VMS Macro 64 assembler only supports 2 operand jmp/jsr instructions. Since it's a hint, you can just drop it. r~