I Wish Intel CPU's Had A Linear Interpolate Instruction
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Posted 28 October 2012 - 02:36 PM
Why linear only, why not all the other interpolation functions?
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Posted 28 October 2012 - 06:58 PM
That said there are more important instructions we need in the future like those predicate instructions to remove branch pipeline flushes.
Edited by Sirisian, 28 October 2012 - 06:58 PM.
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Posted 28 October 2012 - 09:48 PM
DPPS in SSE4 handles the matrix multiplication case perfectly fine. You're not likely to ever see a single matrix multiply instruction on the x64 platform. MADD is about as good as it'll get (i.e. DPPS)
Agreed. Linear interpolation is not even a blip on the performance radar.
Branch misprediction is a big one. Frequent operations like matrix multiply are another big one.
The branch misprediction one is perhaps the largest one I can thank of that stands out as far as performance critical code goes.
Edited by Washu, 28 October 2012 - 09:54 PM.
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Posted 28 October 2012 - 09:58 PM
While we're at it, does x86 have fsel (or conditional-move for all register types)?
Edited by Hodgman, 28 October 2012 - 10:00 PM.
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Posted 28 October 2012 - 11:03 PM
x86 has quite a lot of conditional-move opcodes, but I don't remember if all register types are supported or not. I believe that GPR and FPU registers are supported, but not sure about MMX/XMM/YMM.
Edited by Nypyren, 28 October 2012 - 11:08 PM.
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Posted 29 October 2012 - 07:31 AM
[...] Additionally, Branch Hints were introduced. These hint prefixes are used to help the processor perform better branch prediction.
hwnt - Hint Weakly Not Taken.
hst - Hint Strongly Taken.