From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailserv2.iuinc.com (qmailr@mailserv2.iuinc.com [206.245.164.55]) by puffin.external.hp.com (8.8.7/8.8.7) with SMTP id HAA31432 for ; Tue, 16 Nov 1999 07:01:32 -0700 Sender: rbrad@mailserv2.iuinc.com Message-ID: <383163F5.3B21ECAB@uswest.net> Date: Tue, 16 Nov 1999 07:02:29 -0700 From: Ryan Bradetich MIME-Version: 1.0 To: frowand@cup.hp.com CC: Alex deVries , parisc-linux@thepuffingroup.com Subject: Re: [parisc-linux] arch/parisc/kernel/realmode_setup.c Question References: <38309A65.9CB3DFC4@hp.com> Content-Type: text/plain; charset=us-ascii List-ID: Frank Rowand wrote: > Alex deVries wrote: > > > > On Mon, 15 Nov 1999, Frank Rowand wrote: > > > You don't get to choose. The PDC is either 32 bit or 64 bit. It's not > > > a question of what mode the OS is running in, but what the PDC was > > > compiled for. > > > > Hm. I'm pretty sure that a 32 bit version of HPUX has run on that box as > > well, so wouldn't that mean that it'd have to be a 32 bit PDC? > > > > - Alex > > Nope. The OS has to figure out what type of PDC it is calling, and properly > marshall the arguments for the call. > > -Frank Time for me to show off my ignorance again. :) As I understand it, the PDC is firmware, which all the CPU (in a multiple CPU box) share. I know that when I installed 11.X on this C200 that I was given the choice to install it in 32 bit or 64 bit mode. Does this mean the install disk updates the PDC firmware to boot into either 32-bit or 64-bit mode? Also looking at the PSW definition for the W bit on page 2-7 and page 2-8 of PA-RISC 2.0 Architecture by Gerry Kane: W: Wide 64-bit address formation enabled. When 1, full 64-bit-offset addressing is enabled. When 0, addresses are truncated to 32-bit offsets, for compatibility with existing PA-RISC 1.0 and 1.1 applications.