From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from oss.sgi.com (localhost [127.0.0.1]) by oss.sgi.com (8.12.5/8.12.5) with ESMTP id g6OIajRw004737 for ; Wed, 24 Jul 2002 11:36:45 -0700 Received: (from majordomo@localhost) by oss.sgi.com (8.12.5/8.12.3/Submit) id g6OIajCQ004736 for linux-mips-outgoing; Wed, 24 Jul 2002 11:36:45 -0700 X-Authentication-Warning: oss.sgi.com: majordomo set sender to owner-linux-mips@oss.sgi.com using -f Received: from deliverator.sgi.com (deliverator.SGI.COM [204.94.214.10] (may be forged)) by oss.sgi.com (8.12.5/8.12.5) with SMTP id g6OIafRw004727 for ; Wed, 24 Jul 2002 11:36:41 -0700 Received: from av.mvista.com (gateway-1237.mvista.com [12.44.186.158]) by deliverator.sgi.com (980327.SGI.8.8.8-aspam/980304.SGI-aspam: SGI does not authorize the use of its proprietary systems or networks for unsolicited or bulk email from the Internet.) via ESMTP id LAA07787 for ; Wed, 24 Jul 2002 11:37:43 -0700 (PDT) mail_from (jsun@mvista.com) Received: from mvista.com (av [127.0.0.1]) by av.mvista.com (8.9.3/8.9.3) with ESMTP id LAA02060; Wed, 24 Jul 2002 11:32:30 -0700 Message-ID: <3D3EF0BD.6080508@mvista.com> Date: Wed, 24 Jul 2002 11:23:57 -0700 From: Jun Sun User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:0.9.9) Gecko/20020408 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Nick Zajerko-McKee CC: linux-mips@oss.sgi.com Subject: Re: Question about generic\time.c 2.4.17 References: <1027461913.4699.26.camel@gtlinuxserver1.telogy.design.ti.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Status: No, hits=1.3 required=5.0 tests=MAY_BE_FORGED version=2.20 X-Spam-Level: * Sender: owner-linux-mips@oss.sgi.com Precedence: bulk Nick Zajerko-McKee wrote: > Hi, > > I'm working on a new 4Kc platform and was looking at the > arch\mips\mips-boards\generic\time.c sources. Can someone explain to me > the function of do_fast_gettimeoffset(), especially the do_div64_32() > assembler routine? One of the requirements I have will be not modify > the timer resolution for my platform to something in the msec range w/o > disturbing the underlying jiffie setup found in linux. > do_div64_32() emulate 64bit division with 32bit registers/values. do_fast_gettimeoffset() gives the intra-jiffy time offset, which yields higher timer resolution. Take a look of /Documentation/mips/time.README. Jun