From mboxrd@z Thu Jan 1 00:00:00 1970 From: "H. Peter Anvin" Subject: Re: [ANN] Bochs bios ported to gcc Date: Mon, 07 Apr 2008 09:18:31 -0700 Message-ID: <47FA4957.5010800@zytor.com> References: <20080402014204.GA17824@ohio.lan> <47F8BC77.3060106@qumranet.com> <47F9C243.2060803@zytor.com> <20080407130545.GA22933@ohio.lan> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel@lists.sourceforge.net, Avi Kivity To: "Kevin O'Connor" Return-path: In-Reply-To: <20080407130545.GA22933@ohio.lan> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces@lists.sourceforge.net Errors-To: kvm-devel-bounces@lists.sourceforge.net List-Id: kvm.vger.kernel.org Kevin O'Connor wrote: > On Sun, Apr 06, 2008 at 11:42:11PM -0700, H. Peter Anvin wrote: >> bcc is truly horrible. gcc is, of course, best, although it does produce >> bloated 16-bit code. > > With gcc, the text size has actually been significantly reduced - I'm > not sure if this is because I'm using -fwhole-program and -Os or if it > is just the result of bcc being so bad. > The 16-bit code is still horrid. I have done some experiments with a 16-bit backend to gcc last summer, and even when it could barely crawl, and had effectively no optimizations, it still produced 15% smaller code than the 32-bit backend with .code16gcc and the best optimizations I could find. > The biggest problem I've run into is stack usage on the 16-bit bios > calls. > >> For "proper" 16-bit code, OpenWatcom is currently the >> best open source compiler, and it's actually getting usable even on a Linux >> host. > > One of the developers on the bochs list also recommended OpenWatcom. > > The bios currently has quite a bit of 32bit code in addition to the > 16bit code. It's very convenient to be able to compile the same code > in both modes (eg, printf, inb, etc.). I'd need to move both 32bit > and 16bit code to OpenWatcom to do this. Yes, of course. OpenWatcom does do both, although I think gcc is a better compiler than OpenWatcom in 32-bit mode. OpenWatcom isn't bad, though. As long as it's just C, it's not really an issue, though. -hpa ------------------------------------------------------------------------- This SF.net email is sponsored by the 2008 JavaOne(SM) Conference Register now and save $200. Hurry, offer ends at 11:59 p.m., Monday, April 7! Use priority code J8TLD2. http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone