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The common implementations usually reference: https://github.com/fmatthew5876/stdcxx-bitops/blob/master/include/bitops.hh

I styled my version to match (except for the constexpr macro):

template <typename Integral> constexpr Integral extract_bits(Integral x, Integral mask) { Integral res=0; int bb=1; do { Integral lsb=mask & -mask; mask &= ~lsb; bool isset=x & lsb; res |= isset ? bb : 0; bb+=bb; } while (mask); return res; } template <typename Integral> constexpr Integral deposit_bits(Integral x, Integral mask) { Integral res = 0; int bb=1; do { Integral lsb=mask & -mask; mask &= ~lsb; bool isset=x&bb; res |= (x & bb) ? lsb : 0; bb+=bb; } while(mask); return res; }
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  • \$\begingroup\$ So it looks like you took Matthew Fioravante's version and turned the for-loop in a do-while loop, and the if into a ternary? I'm not really sure this is suitable for Code Review. \$\endgroup\$ Commented Aug 18, 2022 at 20:01
  • \$\begingroup\$ Its the result of quite a bit of optimizing. Take a look at godbolt.org/z/3TqeerMzc \$\endgroup\$ Commented Aug 18, 2022 at 23:25
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    \$\begingroup\$ Yes, I did see the difference in assembly output, and with your changes it is indeed a bit better. However, if you are not the author of the code you post, it's not considered on-topic for CodeReview.. \$\endgroup\$ Commented Aug 19, 2022 at 5:49
  • \$\begingroup\$ ownership can be discussed here: codereview.meta.stackexchange.com/questions/10829/… \$\endgroup\$ Commented Aug 19, 2022 at 12:46
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    \$\begingroup\$ I don't see any macro. Did you intend to write "the constexpr keyword" there? \$\endgroup\$ Commented Aug 20, 2022 at 8:31

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