Path: utzoo!utgpu!watmath!clyde!att!rutgers!mailrus!ames!oli-stl!asylum!romkey
From: romkey@asylum.sf.ca.us (John Romkey)
Newsgroups: comp.binaries.ibm.pc.d
Subject: Re: v01i016: fract386, creates fractal display v2.1 (part 01/02)
Keywords: fract386, VP/ix
Message-ID: <1006@asylum.sf.ca.us>
Date: 29 Nov 88 15:28:05 GMT
References: <588@ctisbv.UUCP>
Reply-To: romkey@asylum.UUCP (John Romkey)
Organization: The Asylum; Belmont, CA
Lines: 16

In article <588@ctisbv.UUCP> pim@ctisbv.UUCP (Pim Zandbergen) writes:
>This is funny, fract386 runs just fine under VP/ix with SCO Xenix.
>VP/ix emulates a 8086 pc. Can anybody explain this?

Sure. VP/ix doesn't really emulate an 8086. It emulates a superset of
an 8086. It precludes you from executing protected mode instructions
and from using 32 bit segments. When you're running in VP/ix, the
processor is still executing the instructions directly, so you can use
the 32 bit-mode prefix on instructions and it will work. Likewise,
instructions like ENTER and LEAVE, which were only added to later
processors than the 8086 also work.
-- 
			- john romkey
romkey@asylum.uucp	romkey@xx.lcs.mit.edu	romkey@asylum.sf.ca.us
Find the cost of freedom, buried in the ground
Mother Earth will swallow you, lay your body down.