[Info-vax] Intel proposal to simplify x86-64

[Arne Vajhøj]

On 6/4/2023 3:31 PM, John Dallman wrote:
> In article <630361da-4c95-4556-b7a6-40cc74829383n at googlegroups.com>,
> n.rieck at bell.net (Neil Rieck) wrote:
>> As far as the Intel proposal is concerned, "I thought" that
>> Microsoft has already blocked running 16-bit programs on their
>> 64-bit OS for a few years now.
> 
> They deliberately left it out of 64-bit Windows from the beginning of
> that OS. The hardware has been capable of running 16-bit code since AMD
> first designed x86-64, but Microsoft only exploited that in 32-bit
> Windows.

Are you sure that was a MS choice?

16 bit programs are a AFAIK not run in "real mode"
but in "virtual 8086 mode".

And based on what I can read then "virtual 8086 mode"
is only available when the system is running in
"32 bit mode" / "protected mode" / "legacy mode" and
not when running in "64 bit mode" / "long mode".

Arne