63
votes
4
answers
974
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Why do x86-64 instructions on 32-bit registers zero the upper part of the full 64-bit register?
In the x86-64 Tour of Intel Manuals, I read Perhaps the most surprising fact is that an instruction such a
50
votes
3
answers
1.7K
views
What is a retpoline and how does it work?
In order to mitigate against kernel or cross-process memory disclosure (the Spectre attack), the Linux kernel1
54
votes
10
answers
1.6K
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What does multicore assembly language look like?
Once upon a time, to write x86 assembler, for example, you would have instructions stating "load the EDX regis
52
votes
4
answers
663
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How do I achieve the theoretical maximum of 4 FLOPs per cycle?
How can the theoretical peak performance of 4 floating point operations (double precision) per cycle be achiev
63
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27
answers
2.9K
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Why is processing a sorted array faster than processing an unsorted array?
Here is a piece of C++ code that shows some very peculiar behavior. For some strange reason, sorting the data
