Re:The NSA Instruction (2019)
by ncmncm on Friday June 11, 2021 @07:11PM
(#27479618)
This seems like a strange question. All computing today uses binary code. We often write things in other bases for convenience, but at the hardware level, it is nothing but ones and zeroes.
But maybe you are asking about uses of independent bits. A maximally efficient representation for a set with a fixed universe of members uses each bit position in a large-enough integer type to represent presence or absence of a possible member. Then, AND and OR operations correspond to set intersection and union operations. C++ provides std::bitset for this use. Useful such sets include days in the week or month, and letters in the alphabet.
The article mentions chess, where you might have a 64-bit word to represent the positions of (say) all the pawns on the board. Fairly simple bitwise operations identify all the positions those pawns threaten.
Modern symmetric cryptographic primitives often use principally bitwise operations, including shifts.
But maybe you are asking about uses of independent bits. A maximally efficient representation for a set with a fixed universe of members uses each bit position in a large-enough integer type to represent presence or absence of a possible member. Then, AND and OR operations correspond to set intersection and union operations. C++ provides std::bitset for this use. Useful such sets include days in the week or month, and letters in the alphabet.
The article mentions chess, where you might have a 64-bit word to represent the positions of (say) all the pawns on the board. Fairly simple bitwise operations identify all the positions those pawns threaten.
Modern symmetric cryptographic primitives often use principally bitwise operations, including shifts.