Date: Sun, 25 Jun 95 18:16:41 MDT From: terry@cs.weber.edu (Terry Lambert) To: bde@zeta.org.au (Bruce Evans) Cc: wpaul@skynet.ctr.columbia.edu, hackers@freebsd.org, rgrimes@gndrsh.aac.dev.com Subject: Re: 2.05R reboot hangs Message-ID: <9506260016.AA13065@cs.weber.edu> In-Reply-To: <199506252337.JAA10041@godzilla.zeta.org.au> from "Bruce Evans" at Jun 26, 95 09:37:34 am
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> Disabled? This seems likely. The linear reset address is not > 0xF000:0xFFF0 or whatever I said before; it is actually > > %eip = 0x0000fff0 + > base(%cs) = 0xffff0000 > = 0xfffffff0 > > This has A20 and other high bits set, so it works properly iff the ROM > is shadowed in high memory at all times. Does GateA20 control A21-31? I think it wraps continuously instead of just once. That's a "yes". The shadowing isn't guaranteed (I don't think). There is also the (potential) isue of lo core data used in the reset. Terry Lambert terry@cs.weber.edu --- Any opinions in this posting are my own and not those of my present or previous employers.
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