[Webkit-unassigned] [Bug 112141] LLInt CLoop backend misses Double2Ints() on 32bit architectures

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=112141





--- Comment #5 from Gabor Rapcsanyi <rgabor at webkit.org>  2013-03-12 09:03:04 PST ---
(In reply to comment #2)
> (From update of attachment 192723 [details])
> View in context: https://bugs.webkit.org/attachment.cgi?id=192723&action=review
> 
> R=me, but it looks like both Ints2Double and Double2Ints are not endianness-friendly.
> 

Nope they don't, should we make it endianness-friendly?

> > Source/JavaScriptCore/llint/LowLevelInterpreter.cpp:130
> > +static void Double2Ints(double val, uint32_t& lo, uint32_t& hi)
> > +{
> > +    union {
> > +        double dval;
> > +        uint64_t ival64;
> > +    } u;
> > +    u.dval = val;
> > +    hi = static_cast<uint32_t>(u.ival64 >> 32);
> > +    lo = static_cast<uint32_t>(u.ival64);
> > +}
> 
> Is this right?  Does Double2Ints mandate 'hi' and 'lo' being the low-order bits and the high-order bits, or are they supposed to be the first bits and the last bits?

I've just made it as the Ints2Double. We tried it on JSC tests and everything went fine. So I think its ok for the little-endian architecture at least.

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