[rust-dev] Fast inverse square root in Rust

Thad Guidry thadguidry at gmail.com
Sun Jan 12 10:19:11 PST 2014


Is that implemented through LLVM at
http://llvm.org/docs/doxygen/html/TargetTransformInfo_8h_source.html

00265   /// haveFastSqrt -- Return true if the hardware has a fast
square-root00266   /// instruction.00267   virtual bool haveFastSqrt
<http://llvm.org/docs/doxygen/html/classllvm_1_1TargetTransformInfo.html#a01138d480dc0f9e11216e65d676a5bb9>(Type
<http://llvm.org/docs/doxygen/html/classllvm_1_1Type.html> *Ty) const;


How does that pass from Rust ???

On Sun, Jan 12, 2014 at 11:51 AM, Owen Shepherd <owen.shepherd at e43.eu>wrote:

> The "Fast inverse square root" is no longer fast. SSE implements accurate
> square root which is faster.
>
> Owen Shepherd
> http://owenshepherd.net | owen.shepherd at e43.eu
>
>
> On 12 January 2014 17:31, Carter Schonwald <carter.schonwald at gmail.com>wrote:
>
>>
>> http://static.rust-lang.org/doc/0.9/std/num/trait.Algebraic.html
>>
>> On Sunday, January 12, 2014, Thad Guidry wrote:
>>
>>> Where is the fast inverse square root function in Rust ?
>>> http://en.wikipedia.org/wiki/Fast_inverse_square_root
>>>
>>> Anyone know if this semi-accurate function is at a hardware level and
>>> built in to Intel chipsets since MMX ?
>>>
>>> How does this affect LLVM and Rust compilation on 64 bit ?
>>>
>>> Thanks in advance,
>>>
>>> --
>>> -Thad
>>> +ThadGuidry <https://www.google.com/+ThadGuidry>
>>> Thad on LinkedIn <http://www.linkedin.com/in/thadguidry/>
>>>
>>
>> _______________________________________________
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>>
>>
>


-- 
-Thad
+ThadGuidry <https://www.google.com/+ThadGuidry>
Thad on LinkedIn <http://www.linkedin.com/in/thadguidry/>
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