From owner-freebsd-hackers Wed Dec 1 14:38:49 1999 Delivered-To: freebsd-hackers@freebsd.org Received: from bingnet2.cc.binghamton.edu (bingnet2.cc.binghamton.edu [128.226.1.18]) by hub.freebsd.org (Postfix) with ESMTP id 02A08151AC for ; Wed, 1 Dec 1999 14:38:43 -0800 (PST) (envelope-from zzhang@cs.binghamton.edu) Received: from sol.cs.binghamton.edu (cs1-gw.cs.binghamton.edu [128.226.171.72]) by bingnet2.cc.binghamton.edu (8.9.3/8.9.3) with SMTP id RAA16859 for ; Wed, 1 Dec 1999 17:38:15 -0500 (EST) Date: Wed, 1 Dec 1999 16:25:22 -0500 (EST) From: Zhihui Zhang To: freebsd-hackers@freebsd.org Subject: memory-to-memory copy Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG I used to know that memory to memory copy is done by the DMA controller in the I/O bridge (Actually, this knowledge confues me because DMA controller normally does not store the data that pass through it. Now the source and destination are both memory, how can it achieve this at the same time with one memory bus?). I was also told that the function bcopy() is used to setup DMA. Now I look at the bcopy() function in i386/support.s, I only see instructions like "rep movsb". So how is the memory-to-memory copy done in FreeBSD? Any help is appreciated. -Zhihui To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message