X86-64 Assembly Language

Question 1

Which of the following about argument registers is false?
A. A function can use any of the arguments registers as temporal variables.
B. After calling a function, the register arguments will not be modified.
C. If you need these registers after the function returns, save them in the stack before calling a function and restore them after it returns.

Answer 1

B.

After calling a function like printf, the register arguments may be modified.

Question 2

If a function uses any of the callee saved, it means that their values do not need to be preserved when the function returns.
True/False

Answer 2

False

Their values need to be preserved when the function returns.

Question 3

Addressing modes:
movq $0x501208, %rdi
A. Direct memory reference
B. Indirect through a register
C. Direct register reference
D. Immediate Value

Answer 3

D

Question 4

Addressing modes:
movq %rsi, (%rdi)
A. Direct memory reference
B. Indirect through a register
C. Direct register reference
D. Immediate Value

Answer 4

B.

Question 5

Addressing modes:
movq %rax, %rdi
A. Direct memory reference
B. Indirect through a register
C. Direct register reference
D. Immediate Value

Answer 5

C

Question 6

Addressing modes:
movq 0x501208, %rdi
A. Direct memory reference
B. Indirect through a register
C. Direct register reference
D. Immediate Value

Answer 6

A

Question 7

The stack is used to:-
store \_\_\_
store \_\_\_
save \_\_\_ when running out of them
pass \_\_\_ when they don't fit in the register

Answer 7

return address; local variable; registers; arguments

Question 8

To create space for a global variable in assembly langauge, use:-
. ___
. comm ___, ___, [___]

Answer 8

data; var_name; data_size; alignment (optional)

Question 9

The size of the registers are ___ bytes long.

Answer 9

8

Question 10

The ___ byte of every register in the x86-64 can be used as a byte register.

Answer 10

lowest