Question

1. How many bits are moved in the instruction as shown below?

mov     al,        bl

2.

how many bits are moved in the instruction as shown below?

mov     ax,       bx

3.

How many bits are moved in the instruction as shown below?

mov eax, ebx

4.

How many bits are moved in the instruction as shown below?

mov     r8,        r9

5.How do you reference r9 as 8 bits?

Answer 1

1) mov al, bl

8-bits are moved because al, bl are referencing lower 8-bits of eax, ebx.

2) mov ax, bx

16-bits are moved because ax, bx are referencing lower 16-bits of eax, ebx.

3) mov eax, ebx

32-bits are moved because eax, ebx are 32-bit registers.

4) mov r8, r9

32-bits are moved because r8, r9 are 32-bit registers.

5) To refer r9 as 8-bits which is a 32-bit register we use following:

   r9b

Here b represent the byte which is 8-bits