We know that memory is addressed by a combination of
(Base+Index*Scale+Displacement). If the code is 16 bit protected mode
and addresses a memory location, can we specify 8 bit registers like
AH, BH .....as base or index registers?
The same question is for a code that is executed in 16 bit real address (or 64 bit mode).
Intel 64 and IA-32 software developer's manual mentions 32 or 64 bit registers in 64 bit mode I think.