[webkit-dev] jit, unordered compare

Geoffrey Garen ggaren at apple.com
Mon Oct 12 14:00:09 PDT 2009

> unfortunately cmf was used by the old fpa (floating point  
> accelerator),
> which is replaced by vfp (vector floating point) for some time.  
> Perhaps I
> can try a "cmpvs reg0, reg0" instruction, which sets zero flag if one
> argument is NaN (since reg0 is always equal to reg0). Otherwise it  
> does
> nothing (=nop).

That should work, but it would require two branches instead of one  
(compare to 0, compare to self).

I'm sure there must be a way to do an IEEE double comparison on ARM  
with only one branch.


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