Do we also refer to the registers RAX, RBX etc as R1, R2 and so on?

Question

I am studying 8086/8080 microprocessors. The registers used in them have names,

1. RAX
2. RBX
3. RCX
4. RDX

and go on until R8 wh

Answer 1

Standard practice is for the first 8 registers to keep their historical name. This convention is used in the documentation from Intel and AMD and in most assemblers.

The reason for this is that these names are mnemonic for the function of the register. For example rsp sticks out as the stack pointer; r4 not so much. The new registers, by contrast, don't have any particular function.

That being said you can always use macros to define r0-r7 as rax,rcx,rdx,rbx,rsp,rbp,rsi,rdi. For example you can get these definitions in nasm with

%use altreg

Again, this is non-standard and will make the code hard to read, both for you and others.