From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 7471 invoked by alias); 21 Apr 2012 19:04:48 -0000 Received: (qmail 7463 invoked by uid 22791); 21 Apr 2012 19:04:47 -0000 X-SWARE-Spam-Status: No, hits=-3.0 required=5.0 tests=AWL,BAYES_00,KHOP_THREADED X-Spam-Check-By: sourceware.org Received: from shards.monkeyblade.net (HELO shards.monkeyblade.net) (198.137.202.13) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Sat, 21 Apr 2012 19:04:10 +0000 Received: from localhost (cpe-66-108-118-54.nyc.res.rr.com [66.108.118.54]) (authenticated bits=0) by shards.monkeyblade.net (8.14.4/8.14.4) with ESMTP id q3LJ49cV023527 (version=TLSv1/SSLv3 cipher=RC4-SHA bits=128 verify=NO); Sat, 21 Apr 2012 12:04:09 -0700 Date: Sat, 21 Apr 2012 22:29:00 -0000 Message-Id: <20120421.150408.2228955493713501659.davem@davemloft.net> To: mark.kettenis@xs4all.nl Cc: gdb-patches@sourceware.org Subject: Re: [PATCH] Handle sparc compare-and-branch From: David Miller In-Reply-To: <201204211011.q3LABYvY005548@glazunov.sibelius.xs4all.nl> References: <20120420.203408.165318333491237734.davem@davemloft.net> <201204211011.q3LABYvY005548@glazunov.sibelius.xs4all.nl> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-IsSubscribed: yes Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org X-SW-Source: 2012-04/txt/msg00715.txt.bz2 From: Mark Kettenis Date: Sat, 21 Apr 2012 12:11:34 +0200 (CEST) >> Date: Fri, 20 Apr 2012 20:34:08 -0400 (EDT) >> From: David Miller >> >> SPARC-T4 adds a "compare and branch" instruction which fuses >> a compare and a branch instruction into one. The branch >> is non-delayed, there are no anulling facilities, and the >> displacement is 10-bits. > > Is this new instruction documented anywhere? Not publicly at the current time, but such documents will be available soon. I've posted binutils patches the other day if you're interested in the opcodes :-) >> This also corrects the existing bit test for Branch on >> Integer Register. The distinguising characteristic between >> Branch on Integer Register and Compare-and-Branch is bit >> 28. The existing code was checking bit 24 for zero, but >> that's pointless because bit 24 is already covered by >> the "X_OP2 (insn) == 3" test. >> >> Ok to commit? > > Makes sense to me, so please go ahead. Thanks.