Re: Ev86 mode and Linux

Gabriel Paubert (paubert@iram.es)
Wed, 10 Dec 1997 11:58:40 +0100 (MET)


On 9 Dec 1997, Linus Torvalds wrote:

> In article <348D7126.B83BA197@quark.vpplus.com>,
> Brian Gerst <bgerst@quark.vpplus.com> wrote:
> >
> >Linux has the ability to use [e]v86 mode, but the only thing that does
> >use it (to my knowledge) is dosemu.
>
> I don't think the extended-v86 mode is documented well enough for it to
> be used. It seems to do much of what the current kernel v86 mode support
> does, except in hardware rather than in software. However, it probably
> doesn't do it quite the same way, and as the interfaces are "Appendix H"
> from Intel, it's hard to find out about them..
>

Actually there is quite a good description (IMHO) of this feature in the
third volume of the PPro documentation (242692_1.pdf), chapter 12.

BTW, it seems OS/2 Warp V3 uses it, unlike Doze'95, which was released
one year later. (1: cli; jmp 1b kills '95 and not OS/2. And at about 10
clocks per iteration on a Pentium under OS/2, it cannot be emulated).

Greetings,
Gabriel.