From mboxrd@z Thu Jan  1 00:00:00 1970
Message-ID: <6459fc9293ea05fe92e4594382a4d30b@quanstro.net>
From: erik quanstrom <quanstro@quanstro.net>
Date: Wed, 22 Aug 2007 21:54:55 -0400
To: 9fans@cse.psu.edu
Subject: Re: [9fans] double-mapping KZERO in l.s
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> But the EIP has to access the instructions. After the mov, you're
> still at low memory. Paging is turned on at this time. The  JMP is
> running at 0x10000something. So you turn paging on and do a jump, but
> paging is on when you do the jmp and fetch from low memory. To make
> the ifetch work you have to have the low map on.
> 
> I'll look at that code tonight again to make sure I'm not imaging
> things, but I think this is right.
> 
> ron

that sounds logical to me, i was thinking that this would work because
the processor had already fetched the next instruction.  but, duh,
	mov x, crn
is a serializing instruction.  (amd arch reference, vol 3, p. 280.)

thanks.

- erik