There are also a few different algorithms to handle it https://graphics.stanford.edu/~seander/bithacks.html#CountBitsSetNaive https://graphics.stanford.edu/~se

There are also a few different algorithms to handle it https://graphics.stanford.edu/~seander/bithacks.html#CountBitsSetNaive https://graphics.stanford.edu/~seander/bithacks.html#CountBi... x86 started as basically a calculator chip. Not a lot of need in that particular space/usecase for it, and more importantly silicon space for it. However, what is interesting is how long it took to add it to the x86 set of instructions. But at least we have it now.