From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 10791 invoked by alias); 16 Feb 2007 20:54:05 -0000 Received: (qmail 10783 invoked by uid 22791); 16 Feb 2007 20:54:04 -0000 X-Spam-Check-By: sourceware.org Received: from mx1.redhat.com (HELO mx1.redhat.com) (66.187.233.31) by sourceware.org (qpsmtpd/0.31) with ESMTP; Fri, 16 Feb 2007 20:53:57 +0000 Received: from int-mx1.corp.redhat.com (int-mx1.corp.redhat.com [172.16.52.254]) by mx1.redhat.com (8.13.1/8.13.1) with ESMTP id l1GKrot1012423 for ; Fri, 16 Feb 2007 15:53:50 -0500 Received: from pobox.toronto.redhat.com (pobox.toronto.redhat.com [172.16.14.4]) by int-mx1.corp.redhat.com (8.13.1/8.13.1) with ESMTP id l1GKroSr015014; Fri, 16 Feb 2007 15:53:50 -0500 Received: from [172.16.14.227] (topaz.toronto.redhat.com [172.16.14.227]) by pobox.toronto.redhat.com (8.12.11.20060308/8.12.11) with ESMTP id l1GKrn73001380; Fri, 16 Feb 2007 15:53:50 -0500 Message-ID: <45D619DD.7010602@redhat.com> Date: Fri, 16 Feb 2007 20:54:00 -0000 From: Dave Brolley User-Agent: Thunderbird 1.5.0.5 (X11/20060719) MIME-Version: 1.0 To: Joern Rennecke CC: "Frank Ch. Eigler" , cgen@sources.redhat.com Subject: Re: delayed branches and zero overhead loops References: <20070213153717.GA12710@elsdt-razorfish.arc.com> <20070213185118.GA20088@redhat.com> <20070213205905.GB16492@elsdt-razorfish.arc.com> <20070213211152.GD20088@redhat.com> <20070213222044.GA31512@elsdt-razorfish.arc.com> <45D34205.9000209@redhat.com> <20070214182926.GA18550@elsdt-razorfish.arc.com> <45D36856.8010208@redhat.com> <20070214201406.GD18550@elsdt-razorfish.arc.com> In-Reply-To: <20070214201406.GD18550@elsdt-razorfish.arc.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-IsSubscribed: yes Mailing-List: contact cgen-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: cgen-owner@sourceware.org X-SW-Source: 2007-q1/txt/msg00052.txt.bz2 Joern Rennecke wrote: > On Wed, Feb 14, 2007 at 02:51:50PM -0500, Dave Brolley wrote: > >> Joern Rennecke wrote: >> >>> That is indeed the case. The only format differences are in the >>> RC-ilink / RC-noilink operand and in the F0 / F1F operand. >>> >>> >>> >> If so, then there must be more bits which are constant in each of the >> two forms of the insn, otherwise, how does the hardware decode them? >> > > ilink1 is core register 29, ilink2 is core register 30 . > Thus, you could describe the upper four bits of RC-ilink as 7, > but that would still not disambiguate it from RC-noilink for core registers > 28 and 31. > I would merge the two insns into one and handle the difference in the semantic code by checking (index-of ) > >>> It's the same situation with long immediates. They are indicated by a >>> special value in any one of three operand fields. >>> This could be handled in the same way by checking the values of the immediate operands. Dave