Huh? x86/x86_64 has segmented registers that can be used as 64 bit (rax), 32 bit (eax), 16 bit (ax), and the upper and lower 8 bits of the latter (ah,al). Not to mention I/O ports which use 16 bit addresses and allow for 8, 16, and 32 bit accesses, and various internal processor data structures that have 8 or 16 bit wide fields, among other uses.