VP/ix and Merge instruction sets (Was: Re: Can protected mode...)

Wm E Davidsen Jr davidsen at crdos1.crd.ge.COM
Tue Nov 28 09:13:51 AEST 1989


In article <128424 at sun.Eng.Sun.COM> plocher at sun.UUCP (John Plocher) writes:

| If the instructions exist on the 8086 you can use them in the
| virtual 8086 mode.  

  Correct.

|                     This is a "hardware" mode of the 80386, not
| a software emulation under Unix.  

  Also correct.

|                                   If the program won't run on
| an IBM XT, it won't run under 80386 VP/ix or 80386 Merge.

  Grain of truth. If a program runs using protected mode it won't run
under V86 mode. But there are programs which won't run on an XT which
do run on a 386, under DOS or V86 mode. Any program which uses only the
32 bit arithmetic instructions will run fine (and much faster). It may
NOT use the protected mode, nor addressing modes not available on the
8088.

  I know what you meant, but what you said was wrong. The arithmetic IS
available, the addressing modes are NOT available.
-- 
bill davidsen	(davidsen at crdos1.crd.GE.COM -or- uunet!crdgw1!crdos1!davidsen)
"The world is filled with fools. They blindly follow their so-called
'reason' in the face of the church and common sense. Any fool can see
that the world is flat!" - anon



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