Re: LOADALL and the 486

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Article #924

#924

From: Joao Prospero Luis [ps]
Date: Mon, 09 Nov 1992 11:55

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Marcus Jenkins (marcusj@apricot.co.uk) wrote:
: I know this may be an FAQ, but I am just a little confused.  Is
: LOADALL implemented in the 486?  PC Magazine said that it is
: in all processors from 2-486.  It also said that Microsoft use
: the instruction in HIMEM.SYS, SMARTDRV.SYS and RAMDRIVE.SYS in
: MS-DOS.  On the other hand, an instructor from Intel (while lecturing
: on an i386/486 programming and architecture course) alleged that
: LOADALL is only there on 286 and earlier steps of the 386.  Does
: anybody know the REAL answer?  Is there commercial software out
: there that does use this reserved instruction.  This enquiry is
: out of curiosity only - I have no intention of putting LOADALL
: into any of my programs!

	As far as I know (it isnt that much) LOADALL isnt implemented in
the 386, but is simulated by some BIOSes. When it traps an invalid opcode
it goes to check if it is a LOADALL, if it is it is simulated otherwise
it does something else (in fact I think it tests some other invalid opcode
first but I dont remember which). This was confirmed with my AMI BIOS.

	JPL

--
Joao Prospero Luis                 |
Universidade Nova de Lisboa        | Internet: jpl@fct.unl.pt
Faculdade de Ciencias e Tecnologia |
Departamento de Informatica        | Fax:   (+351) (1) 295-5641
2825 Monte Caparica, PORTUGAL      | Phone: (+351) (1) 295-4464

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From: jpl@antares.fct.unl.pt (Joao Prospero Luis [ps])
Subject: Re: LOADALL and the 486
Message-ID: <1992Nov9.115520.5893@fct.unl.pt>
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Date: Mon, 9 Nov 1992 11:55:20 GMT
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