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To: Terry Lambert <terry@lambert.org>
cc: smp@csn.net (Steve Passe), smp@FreeBSD.ORG, current@FreeBSD.ORG
Subject: Re: self modifying kernel code 
In-reply-to: Your message of "Wed, 16 Jul 1997 14:41:26 PDT."
             <199707162141.OAA01599@phaeton.artisoft.com> 
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Date: Wed, 16 Jul 1997 15:45:25 -0700
From: Wayne Scott <wscott@ichips.intel.com>
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> Are we assuming that the processors will be Pentium only?  The icache
> is not written back prior to the P5.  This takes a significant number
> of NOP's to flush the pipeline (as discussed in Van Guilluwe's "The
> Undocumented PC" in the section where he investigates instruction cache
> depth using self-modifying code).

At startup the call is to a routine that computes the correct target
address.  In the fixup routine you change the call address and then
jump to the target directly.  It will be a long time before you
actually execute the modified code.

-Wayne

Wayne Scott		        MD6 Architecture
wscott@ichips.intel.com		Work #: (503) 264-4165
Disclaimer:  All views expressed are my own opinions, and not necessarily 
             those of Intel Corporation.