From:	mharris AT blackwidow DOT saultc DOT on DOT ca
Date:	Tue, 4 Feb 1997 22:56:59 -0500 (EST)
Reply-To:	mharris AT blackwidow DOT saultc DOT on DOT ca
To:	Bartosz Polednia <bartosz AT bielbit DOT bielsko DOT pl>
cc:	chambersb AT juno DOT com, opendos AT mail DOT tacoma DOT net
Subject:	Re: [opendos] speeding up command.com
In-Reply-To:	<s2f5dd7c.004@bielbit.bielsko.pl>
Message-ID:	<Pine.LNX.3.95.970204225038.166v-100000@capslock.com>
Organization:	Total disorganization.
MIME-Version:	1.0
Sender:	owner-opendos AT mail DOT tacoma DOT net

On Mon, 3 Feb 1997, Bartosz Polednia wrote:

> > Question:
> > OpenDOS is for x86 processors, right?
> > THEN WHO THE HELL NEEDS IT TO BE PORTABLE?????????
> > You're not going to break things by inserting a little ASM code - >
> > it's not like it'll run on the Mac anyways :) :) :)
> > And who's going to be running the command.com from Linux???  Go
> > ahead and make things fast!
> 
> Hi,
> 
> #1.
>   What kind video card do you want to implement direct writes for ?
>      If it is VGA, what about all Hercules, EGA, CGA users ?

All.  All cards start at either B800 or B000.  Simple.  Put a
conditional in to see what mode the card is in and then change
your base address for writes.  Takes only a few lines of code.
Piece o cake.

>   Maybe we can use some 386, 486, 586 or MMX specyfic opcodes inside
> Open DOS. Executables will be smaller and faster but all machines
> with less than (386...MMX) could be dropped into trash.

As for the 3,4, and 586 stuff, I'm sure it will happen as soon as
the sources are released.  As for MMX, I don't see what place MMX
instructions would have inside the OS.  Do you want an AVI to
play during booting?  :o) 

As for the 386 and 486 not understanding MMX, just write an MMX
emulator.  It would work in a similar manner to the FPU
emulator by triggering on the unknown instruction exception.  I'm
sure one will be out before you can shake a stick. :o)  


Mike A. Harris        |             http://blackwidow.saultc.on.ca/~mharris
Computer Consultant   |    My webpage has moved and my address has changed.
My dynamic address: http://blackwidow.saultc.on.ca/~mharris/ip-address.html
mailto:mharris AT blackwidow DOT saultc DOT on DOT ca

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