From owner-freebsd-alpha Mon Sep 7 03:41:07 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id DAA20915 for freebsd-alpha-outgoing; Mon, 7 Sep 1998 03:41:07 -0700 (PDT) (envelope-from owner-freebsd-alpha@FreeBSD.ORG) Received: from fleming.cs.strath.ac.uk (fleming.cs.strath.ac.uk [130.159.196.126]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id DAA20910 for ; Mon, 7 Sep 1998 03:41:05 -0700 (PDT) (envelope-from roger@cs.strath.ac.uk) Received: from muir-10 (roger@muir-10.cs.strath.ac.uk [130.159.148.10]) by fleming.cs.strath.ac.uk (8.8.8/8.8.8) with SMTP id LAA02169 Mon, 7 Sep 1998 11:41:00 +0100 (BST) Message-ID: <35F3B83B.167E@cs.strath.ac.uk> Date: Mon, 07 Sep 1998 11:40:59 +0100 From: Roger Hardiman Organization: University of Strathclyde X-Mailer: Mozilla 3.04Gold (X11; I; OSF1 V4.0 alpha) MIME-Version: 1.0 To: freebsd-alpha@FreeBSD.ORG Subject: Bt848 driver for Alpha Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-freebsd-alpha@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org Hi, A question on porting the bt848 driver to Alpha hardware. Anyway, there are 2 32bit dependent sections a) memory mapped registers in the bt848 chip b) RISC code Q) The driver maps the registers (of which the bt848/878 has around 30) into the memory space and then writes to the registers as if you were writing to a normal variable (crude example bt848->register1 = some_value; bt848->register2 = some_value; Question: Can I write to just a 32 bit register with the Alpha. (in the same memory mapped way) Or, does the Alpha sneakilly do a 32 bit read of address n+1 and then do a 64 bit write. (think some old Alpha chips did this) I do not want to go writing to registers I was not intending to write to. Roger Hardiman Strathclyde Uni Telepresence Group To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-alpha" in the body of the message