Aside: adding a native population count function might well be a useful
addition to the library...
Native clz/ctz (_BitScanReverse/_BitScanForward) might be useful as well.
The limb size is always half the width of the largest compiler supported
integer type - this is a necessary condition to implement arithmetic
entirely within the language.
This seems a high price to pay [I guess the 'within the language' is key here]. At some point in time [when 64-bit started to be a general thing] there was some info regarding this on
gmplib.org, which basically stated that 64-bit limbs [on x64] were 4 times faster than 32-bit limbs. GMP (MPIR) does 64-bit limbs on Windows, no problem [but yes it's C].
If clang-win can have __int128 support enabled
clang-cl can/will have
__int128 support enabled by passing it '-Xclang -fforce-enable-int128', i.e. pass '-fforce-enable-int128' to clang++.
degski