Question

ASSEMBLY: Identify which of the following addressing modes are illegal, explain why it is illegal.

A) mov bl, [rbx][rbx]

B) mov ebx, [cs]

C) mov ah, [rbp][rbx]

D) mov ax, [rbp*10]

E) mov bx, [rax*8][rbp][-7]

F) mov dx, [rbp*1][rax*8]

G) mov r15, [VTable+rax][rcx]

H) mov rbp, [rsp+rax]

I) mov cl, [rdx][rax*8]

J) mov ax, [ah][al]

Answer 1

Answer

Below are the illegal addressing modes:
A) mov bl, [rbx][rbx]
C) mov ah, [rbp][rbx]
E) mov bx, [rax*8][rbp][-7]
F) mov dx, [rbp*1][rax*8]
G) mov r15, [VTable+rax][rcx]
I) mov cl, [rdx][rax*8]
J) mov ax, [ah][al]

In the assembly instruction one must choose maximum of one item from the group of displacement, base and offset.