Pretty much all "64-bit" CPU architectures out there also have specific instructions for 32-bit arithmetic. They were designed that way partly on purpose, to c

Pretty much all "64-bit" CPU architectures out there also have specific instructions for 32-bit arithmetic. They were designed that way partly on purpose, to cater for the enormous amount of existing program code that has been written with the assumption that an `int` is 32 bits. A large portion of that code also written with the assumption that they are also 2's complement and wrapping.