I wander if anybody has info that API calls can trash MMX(fpu) regs or change tags?
Posted on 2002-05-14 07:09:09 by The Svin
Nope! I "believe" that the win32 API just uses the "normal" registers(eXx) when using an x86. Probably, because windows has multi-processor support and there are some type of processors that doesn't support MMX. :)
Posted on 2002-05-14 17:55:18 by stryker
I wouldn't be surprised if some APIs use floatingpoint, especially
ones dealing with font output. I would expect at least the documented
apis to not trash the fpu stack, but there might be control word
fumbling going on (I belive DX fiddles with it, but not sure).
However, I've not seen any official documentation, so... time to
do some empirical tests? :)
Posted on 2002-05-14 18:26:02 by f0dder
It might be safer to just assume they're trashed IMO...

Can't ever be too sure if new versions *might* start using that sort of stuff for better efficiency...

'Course it's going to cost you some efficiency if you assume that... maybe empirical tests are better, and hope that newer versions of Windows don't suddenly use them...
Posted on 2002-05-15 08:52:16 by AmkG