[ODE] Re: Deterministic simulation on multiple clients

Jon Watte hplus-ode at mindcontrol.org
Mon Mar 21 12:49:30 MST 2005


> Is this the sort of thing that OS's also guarantee to preserve
> as part of the saved FPU state across a context-switch?  Otherwise I
> can envisage the nightmare of a context-switch to another process (or
> thread) that changes FPU precision on you mid-step.  Brr.

An OS will generally preserve this set across pre-emption context 
switches, but not necessarily through things like structured exception 
handlers, signal handlers or longjumps. Also, many libraries you link 
with may have their own idea of what the rounding mode or precision 
mode should be. (DirectX is really bad; OpenGL sometimes interferes 
too)

Cheers,

			/ h+




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