Registers Flashcards
learn about Registers
1
Q
Questions 6, 7, 8and 9 all refer to the following values in registers and memory of an Intel computer.
Registers %rax 0x800 %rbx 0x410 %rdx 0x004 %rsi0xFFFFFFFFFFFFFFFF
Memory Address - Value 0x800 -----0xFF 0x804 -----0x41 0x808 -----0x04 0x80c ------0xFFFFFFFFFFFFFFF
- For the assembly instruction movq 0x8(%rax, %rdx), %r8 what value is placed in %r8?
A
Answer: -1
movq 0x8(%rax, %rdx), %r8
movq means move quadword to register %r8.
%r8 = M[Imm + %rax + %rdx] %r8 = M[0x8 + 0x800 + 0x004] %r8 = M[ 0x80c ] %r8 = 0xFFFFFFFFFFFFFFF or -1
0x 008 0x 800 0x 004 -------------- 0x 80c
2
Q
Questions 6, 7, 8and 9 all refer to the following values in registers and memory of an Intel computer.
Registers %rax 0x800 %rbx 0x410 %rdx 0x004 %rsi0xFFFFFFFFFFFFFFFF
Memory Address - Value 0x800 -----0xFF 0x804 -----0x41 0x808 -----0x04 0x80c ------0xFFFFFFFFFFFFFFF 7. For the assembly instruction movq -0x18(, %rbx, 2), %r8 what value is placed in %r8?
A
Answer: 0x04
movq -0x18(, %rbx, 2), %r8 what value is placed in %r8?
means move quadword to register %r8
%r8 = M[Imm + (%rbx * 2)] %r8 = M[-0x18 + (0x410 * 2)] %r8 = M[-0x18 + 0x820] %r8 = M[0x 808] %r8 = 0x04
0x 410 x 2 ------------- 0x 820 - 0x 018 -------------- 0x 808
3
Q
Questions 6, 7, 8and 9 all refer to the following values in registers and memory of an Intel computer.
Registers %rax 0x800 %rbx 0x410 %rdx 0x004 %rsi0xFFFFFFFFFFFFFFFF
Memory Address - Value 0x800 -----0xFF 0x804 -----0x41 0x808 -----0x04 0x80c ------0xFFFFFFFFFFFFFFF
- For the assembly instruction movq 0x804(%rdx), %r8 what value is placed in %r8
A
Answer: 0x04
movq 0x804(%rdx), %r8 means move quadword to register %r8
%r8 = M[Imm + %rdx] %r8 = M[0x804 + 0x004] %r8 = M[0x808] %r8 = 0x04
4
Q
Questions 6, 7, 8and 9 all refer to the following values in registers and memory of an Intel computer.
Registers %rax 0x800 %rbx 0x410 %rdx 0x004 %rsi 0xFFFFFFFFFFFFFFFF
Memory Address - Value 0x800 -----0xFF 0x804 -----0x41 0x808 -----0x04 0x80c ------0xFFFFFFFFFFFFFFF
- For the assembly instruction leaq-0xC(%rax, %rsi, 4), %r8 what value is placed in %r8?
A
Answer: 0x7F0
leaq-0xC(%rax, %rsi, 4), %r8
means “load effective address” value
%r8 = M[-0xC + %rax + (%rsi * 4)]
-0x 001 x 4 -------------- -0x 004 \+ -0x 00C -------------- 0x 010
0x 800
- 0x 010
————-
0x 7F0
