From owner-freebsd-current Sat Jun 1 0:35:46 2002 Delivered-To: freebsd-current@freebsd.org Received: from swan.mail.pas.earthlink.net (swan.mail.pas.earthlink.net [207.217.120.123]) by hub.freebsd.org (Postfix) with ESMTP id 1124237B405 for ; Sat, 1 Jun 2002 00:35:43 -0700 (PDT) Received: from pool0040.cvx40-bradley.dialup.earthlink.net ([216.244.42.40] helo=mindspring.com) by swan.prod.itd.earthlink.net with esmtp (Exim 3.33 #2) id 17E3QK-00028t-00; Sat, 01 Jun 2002 00:35:40 -0700 Message-ID: <3CF8792C.FB0B94C1@mindspring.com> Date: Sat, 01 Jun 2002 00:35:08 -0700 From: Terry Lambert X-Mailer: Mozilla 4.7 [en]C-CCK-MCD {Sony} (Win98; U) X-Accept-Language: en MIME-Version: 1.0 To: Jake Burkholder Cc: Julian Elischer , FreeBSD current users Subject: Re: Seeking OK to commit KSE MIII-again References: <20020531133212.U62759@locore.ca> <20020531203317.W62759@locore.ca> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG Jake Burkholder wrote: > The system call stubs in libc are leaf functions; basically just a > trap instruction followed by a return. They do not touch the stack > at all, or change the stack pointer. One of the first few instructions > on entry to the kernel is a save, which rotates the register window > and logically saves the call-safe registers onto the user stack > (the outs become the ins, and the kernel gets new ins and locals, > with the old ones being saved to the user stack once a flush is > performed or they get spilled out). > > Here is a reference: http://www.sparc.com/standards/v9.ps.Z Cool. Thanks for the reference. Though I think it's largely equivalent to the system call helper for threads context and stack switching in liblwp... 8-). -- Terry To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message