From owner-freebsd-hackers Sat Apr 3 11:17: 4 1999 Delivered-To: freebsd-hackers@freebsd.org Received: from quackerjack.cc.vt.edu (quackerjack.cc.vt.edu [198.82.160.250]) by hub.freebsd.org (Postfix) with ESMTP id 1F0DF14E16 for ; Sat, 3 Apr 1999 11:17:01 -0800 (PST) (envelope-from jobaldwi@vt.edu) Received: from sable.cc.vt.edu (sable.cc.vt.edu [128.173.16.30]) by quackerjack.cc.vt.edu (8.8.8/8.8.8) with ESMTP id OAA09526; Sat, 3 Apr 1999 14:15:00 -0500 (EST) Received: from john.baldwin.cx (jobaldwi.campus.vt.edu [198.82.67.63]) by sable.cc.vt.edu (8.8.8/8.8.8) with ESMTP id OAA18405; Sat, 3 Apr 1999 14:15:00 -0500 (EST) Message-ID: X-Mailer: XFMail 1.3 [p0] on FreeBSD X-Priority: 3 (Normal) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8bit MIME-Version: 1.0 In-Reply-To: Date: Sat, 03 Apr 1999 14:15:00 -0500 (EST) From: John Baldwin To: Alfred Perlstein Subject: Re: What does the "s" in insl and insw mean? Cc: freebsd-hackers@FreeBSD.ORG, zhihuizhang Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On 03-Apr-99 Alfred Perlstein wrote: > On Sat, 3 Apr 1999, zhihuizhang wrote: > >> >> The instructions insl() and insw() should read a long word (l) or a word >> (w) from a specified I/O port. But what does the "s" in both instructions >> stand for? I can not find it in the Info files. > > in from port string operation > > it grabs a byte/word from the port, stores it into DS:DI and increments > DI, (that's in x86 real mode) afaik in prot mode it prolly just stores > to the segemtn pointed to DS and uses EDI. > > The opcodes without 's' use al/ax/eax for the destination. > > -Alfred Actually, ins* use ES, not DS, and ignore segment overrides to boot. Also, if the direction flag is set via std, (E)DI is decremented instead of incremented. --- John Baldwin -- http://members.freedomnet.com/~jbaldwin/ PGP Key: http://members.freedomnet.com/~jbaldwin/pgpkey.asc "Power Users Use the Power to Serve!" - http://www.freebsd.org To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message