Back to home page

DOS ain't dead

Forum index page

Log in | Register

Back to the forum
Board view  Mix view

SSE in DOS under JEMM386 ?? (DOSX)

posted by Rugxulo Homepage, Usono, 09.01.2008, 01:23

> > At least, from what I gather,
> > you have to turn on the MP bit and turn off the EM bit in CR0 and then
> > enable OSFXSR in CR4.
>
> ???. Sounds cool at least!

Turn off the Emulate Math bit and turn on the Monitor Processor bit (something about FPU WAIT or whatever). Then, turn on the OSFXSR bit (if available, to tell the cpu that the OS supports SSE).

> What do you mean with "without the need for FXSAVE/FXRSTOR"? These are
> simple application level instructions.

I think Windows does FXSAVE/FXRSTOR for you, hence the idea that the OS needs to support it. (At least, saving/restoring manually just slows it down a lot, at least under XP, because it's already doing so, at least from what I can tell under OpenWatcom's WD.)

---
Know your limits.h

 

Complete thread:

Back to the forum
Board view  Mix view
22049 Postings in 2034 Threads, 396 registered users, 273 users online (0 registered, 273 guests)
DOS ain't dead | Admin contact
RSS Feed
powered by my little forum