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<p class=MsoNormal>Hi all,<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>I’d like to make use of some specific x86 Streaming
SIMD Extension instructions, but I don’t know where to start. For
instance the ‘rcpps’ instructions computes a low precision but fast
reciprocal. I’ve noticed that LLVM supports intrinsics, but I couldn’t
find any information on how to use them. I’ve tried digging through the
LLVM-GCC code but it’s just too complex for me. I would be very grateful
if someone could complete this code:<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;
font-family:"Courier New"'>LoadInst *x = <span style='color:blue'>new</span>
LoadInst(ptr_x, <span style='color:#A31515'>""</span>, <span
style='color:blue'>false</span>, basicBlock);<o:p></o:p></span></p>
<p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;
font-family:"Courier New"'>// y = rcpps(x) // FIXME<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Courier New"'>StoreInst
*storeResult = <span style='color:blue'>new</span> StoreInst(y, ptr_y, <span
style='color:blue'>false</span>, basicBlock);</span><o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Somewhat related to this, I’d also like to know how to
‘reinterpret_cast’ values. It can be quite useful to sometimes
interpret a vector of floating-point values as a vector of integers (for
instance to extract the sign, exponent and/or mantissa bits). Any information
on how to do that would be much appreciated.<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Thanks,<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Nicolas Capens<o:p></o:p></p>
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