From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=53867 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1OmORd-0003Wo-44 for qemu-devel@nongnu.org; Fri, 20 Aug 2010 06:03:33 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.69) (envelope-from ) id 1OmOOi-0008DV-Cl for qemu-devel@nongnu.org; Fri, 20 Aug 2010 06:00:29 -0400 Received: from fe02x03-cgp.akado.ru ([77.232.31.165]:52954 helo=akado.ru) by eggs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1OmOOi-0008CS-4y for qemu-devel@nongnu.org; Fri, 20 Aug 2010 06:00:28 -0400 Date: Fri, 20 Aug 2010 14:00:13 +0400 (MSD) From: malc Subject: Re: [Qemu-devel] [PATCH v2 0/7] APIC/IOAPIC cleanup In-Reply-To: <4C6DD3DE.506@codemonkey.ws> Message-ID: References: <4C6D86F9.3010602@codemonkey.ws> <4C6D98E7.9020109@codemonkey.ws> <4C6DA75D.40303@codemonkey.ws> <4C6DD3DE.506@codemonkey.ws> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Anthony Liguori Cc: Blue Swirl , "Liu >> \"Liu, Jinsong\"" , Paul Brook , Avi Kivity , qemu-devel On Thu, 19 Aug 2010, Anthony Liguori wrote: > On 08/19/2010 05:52 PM, malc wrote: > > > Yes, but the programming model was different. > > > > > > Look at the PIC compared to the lapic. The PIC is programmed via pio at a > > > fixed location. There is only one PIC and it interacts with the system > > > just > > > like all other devices. IOW, there is no reference to CPUState. > > > > > There are two PICs actually there's a cascade.. > > > > Technically speaking, originally there was just one and then more IRQs were > supported by cascading and reserving an IRQ line for supporting cascading. I > think you can technical cascade with any IRQ and have more than one slave but > the historic PC architecture only had one slave AFAIK. One master + one slave = 2 PICs, i guess you've meant that originally there was no slave. [..snip..] -- mailto:av1474@comtv.ru