Programming Question (kinda video related)

[Sarreq Teryx]

considering this article: http://www.siliconstrategies.com/story/OEG...EG20030320S0053 (http://www.siliconstrategies.com/story/OEG20030320S0053)
Microsoft is being very cagey about releasing a x86-64 (hammer) compatible Windows of any type. Now the question is, while running a 32bit OS on a CPU capable of 64bit processing, can programs be written to use the 64bit mode even if the OS doesn't use it itself?

I know they probably wouldn't be able to access memory above what the OS can (4GB), but otherwise, can a program run in 64bit mode on a modern 32bit OS?

I know in the DOS days we had things like DOS4GW to switch from 8/16bit mode to 32bit mode, would a similar method work now?

I'd think video encoding and possibly filtering would benefit from being 64bit capable, higher i/DCT precision, quite possibly alot faster even, even if it couldn't take advantage of more than 4GB of RAM due to possible 32bit OS restrictions.

[gabest]

Originally posted by Sarreq Teryx
I know they probably wouldn't be able to access memory above what the OS can (4GB), but otherwise, can a program run in 64bit mode on a modern 32bit OS?No.I know in the DOS days we had things like DOS4GW to switch from 8/16bit mode to 32bit mode, would a similar method work now?As fas as I know those were OS/2 executables, dos4gw "simulated" the needed environment over DOS.I'd think video encoding and possibly filtering would benefit from being 64bit capable, higher i/DCT precision,Not the 64 bit registers could increase performance (with SIMD it was already possible), but the larger number of general use registers.

[Sarreq Teryx]

Originally posted by gabest
As fas as I know those were OS/2 executables, dos4gw "simulated" the needed environment over DOS. It was also a DOS 32bit mode extender, one of the more popular ones, mostly used for games, I had an amiga module player (it was originally created for OS/2, but ported to DOS, I wish I could remember the name) that used it also

edit: sorry didn't read you right the first time. I guess that's how that one worked, but you actually had to have a 32bit processor to use it with, it's not like it emulated 32bits within 16bit mode, that would've been slow as all hell. but there were several of the things, and I'm sure they didn't all work by providing OS/2 functions to DOS

[gabest]

Hehe, I said that because I remembered that once my friend in collage mentioned that he could run those PE binaries on OS/2 without the help of dos4gw.