From owner-freebsd-amd64@FreeBSD.ORG Thu Mar 15 11:37:40 2012 Return-Path: Delivered-To: freebsd-amd64@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 2EB19106566B for ; Thu, 15 Mar 2012 11:37:40 +0000 (UTC) (envelope-from areilly@bigpond.net.au) Received: from nschwmtas03p.mx.bigpond.com (nschwmtas03p.mx.bigpond.com [61.9.189.143]) by mx1.freebsd.org (Postfix) with ESMTP id A6F8C8FC16 for ; Thu, 15 Mar 2012 11:37:39 +0000 (UTC) Received: from nschwotgx01p.mx.bigpond.com ([124.188.161.100]) by nschwmtas03p.mx.bigpond.com with ESMTP id <20120315113738.UAIR11739.nschwmtas03p.mx.bigpond.com@nschwotgx01p.mx.bigpond.com>; Thu, 15 Mar 2012 11:37:38 +0000 Received: from johnny.reilly.home ([124.188.161.100]) by nschwotgx01p.mx.bigpond.com with ESMTP id <20120315113738.WPQZ2024.nschwotgx01p.mx.bigpond.com@johnny.reilly.home>; Thu, 15 Mar 2012 11:37:38 +0000 Date: Thu, 15 Mar 2012 22:37:27 +1100 From: Andrew Reilly To: Peter Wemm Message-ID: <20120315113727.GB35074@johnny.reilly.home> References: <4F3EA37F.9010207@speakeasy.org> <4F3EC0B4.6050107@speakeasy.org> <4F4DA398.6070703@speakeasy.org> <20120229161408.G2514@besplex.bde.org> <4F4DDCE7.9000008@speakeasy.org> <20120229192417.U3167@besplex.bde.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.3i X-SIH-MSG-ID: qRsyFN35TAD0zmQs0WyzOwJxyArnqyN48Z4QX81loRIGTUDCp8DeQ9rHK+ZRvN+kxD9JJhuENGInaa/sTY3Rs9uK Cc: freebsd-amd64@freebsd.org Subject: Re: Gcc46 and 128 Bit Floating Point X-BeenThere: freebsd-amd64@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Porting FreeBSD to the AMD64 platform List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 15 Mar 2012 11:37:40 -0000 On Wed, Feb 29, 2012 at 11:10:12PM -0800, Peter Wemm wrote: > This is what he's getting at. If he could get access to 128 bit fp, > he could move between 1/2 and 2/3 of the work into hardware operations > and bypass a large chunk of GMP work which would be many many times > slower than 128 bit hardware FP. You make it sound as though "128 bit hardware FP" exists. Bruce's point (I'm fairly certain) is that there's no such thing (at least in the x86 world: could be different in IBM Power series, not sure.) Have I missed a press release or tech doc? AVX, just like SSE{2,3,4} only does 64-bit double: everything else is software. Cheers, -- Andrew