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Date: Fri, 11 Apr 1997 03:05:12 +1000
From: Bruce Evans <bde@zeta.org.au>
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To: guido@gvr.win.tue.nl, peter@freefall.freebsd.org
Subject: Re: cvs commit:  src/sys/i386/i386 genassym.c machdep.c trap.c src/sys/i386/include pcb.h
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>>   This change makes VM86 mode harder, but the following commits will remove
>>   a lot of constraints for the VM86 system, including the possibility of
>>   extending the pcb for an IO port map etc.
>
>Yes! Finally get rid of the old /dev/io hack ;-)

It would mainly make things more complicated and cost more.  Accesses
through the port map cost 20 cycles extra.  There would be up to 64K of
ports to manage.  Who knows where the DMA ports (if any) on new video
cards are?

Bruce