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From: dmurdoch@watstat.waterloo.edu (Duncan Murdoch)
Newsgroups: comp.os.msdos.programmer
Subject: Re: Physical addresses in protected mode?
Message-ID: <1991Jun25.023154.16683@maytag.waterloo.edu>
Date: 25 Jun 91 02:31:54 GMT
References: <cchapman.677508274@msd> <4948@gumby.Altos.COM>
Sender: news@maytag.waterloo.edu (News Owner)
Organization: University of Waterloo
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In article <4948@gumby.Altos.COM> rcollins@altos.COM (Robert Collins) writes:
>
>If you are in V86 mode, then give it up because you are executing at IOPL=3
>which makes it impossible to get the physical address.

If running under VCPI, there's a call to find the physical address corresponding
to any V86 address.  This is done by calling INT 67h with AX=0DE06h, CX=the
linear V86 address shifted right 12 bits.  It returns with EDX holding the
physical address of the page.  I imagine DPMI has a similar service, but
I don't have the spec.

Duncan Murdoch
dmurdoch@watstat.waterloo.edu