[ODE] Replays via recorded user input

[ODE User]

> compatibility question (see below). I think if the floating point 
> calculations are IEEE standard then replay like this should be 
> viable. And at any rate, the problem would not be in ODE. 

Don't be too sure. I've found that some popular graphics drivers 
will change the FPU rounding mode in effect on the CPU under certain 
conditions. Also, sometimes structured exceptions (Windows) or 
signal handlers (Linux) may change the rounding mode without re-
setting it.

We have code that checks the FPU control register once per frame, 
and if it's not what we expect it to be, re-sets it. Note that 
testing the rounding mode is cheap, whereas changing it is more 
expensive (a full CPU pipeline flush, at the very least).

Cheers,

				/ h+