From owner-cvs-all Sat Nov 16 10: 9: 1 2002 Delivered-To: cvs-all@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id CACB837B401; Sat, 16 Nov 2002 10:08:59 -0800 (PST) Received: from mail.pcnet.com (mail.pcnet.com [204.213.232.4]) by mx1.FreeBSD.org (Postfix) with ESMTP id 42EFE43E42; Sat, 16 Nov 2002 10:08:59 -0800 (PST) (envelope-from eischen@pcnet1.pcnet.com) Received: from localhost (eischen@localhost) by mail.pcnet.com (8.12.3/8.12.1) with ESMTP id gAGI8wJs024154; Sat, 16 Nov 2002 13:08:58 -0500 (EST) Date: Sat, 16 Nov 2002 13:08:58 -0500 (EST) From: Daniel Eischen To: Marcel Moolenaar Cc: cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: Re: cvs commit: src/lib/libc_r/arch/ia64 _atomic_lock.S In-Reply-To: <200211161705.gAGH56v5058239@repoman.freebsd.org> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-cvs-all@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG On Sat, 16 Nov 2002, Marcel Moolenaar wrote: > marcel 2002/11/16 09:05:06 PST > > Modified files: > lib/libc_r/arch/ia64 _atomic_lock.S > Log: > Implement the lock with a cmpxchg instruction instead of a xchg. > Both are atomic, but the cmpxchg has memory ordering hints. We > give this acquire semantics. > > NOTE: The unlock in libc_r is implemented by a "normal" assign > statement. This is not correct on ia64 due to the memory ordering > characteristics of the architecture. We need release semantics > for an unlock. We can fix that before 5.0 goes out. -- Dan Eischen To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message