Machine-Level & Systems Programming - Set 1

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1. What kind of data does the DX data directive have?
initialized data
2. What kind of data does the RESX directives have?
uninitialized data
3. What is the size in bytes of: B
byte, 1 byte
4. What is the size in bytes of: W
word, 2
5. What is the size in bytes of: D
double word, 4
6. What is the size in bytes of: Q
quad word, 8
7. What is the size in bytes of: T
ten bytes, 10
8. What does the D in DX directives stand for?
defined
9. What does the RES in RESX directives stand for?
reserved
10. What is the DX label?
the name used in the program to refer to that zone of memory. A pointer to the zone of memory i.e. an address
11. What does the X in DX represent?
the appropriate letter for the size of the data being declared (B for byte, W for word, etc.)
12. DX data directive initial value:
What is default?
decimal
13. DX data directive initial value:
What is b
binary
14. DX data directive initial value:
What is h?
hexadecimal
15. DX data directive initial value:
What is o?
octal
16. DX data directive initial value:
What do quotes represent?
ASCII
17. What is 'A' in decimal and hexadecimal?
65d / 41h
18. What is 'a' in decimal and hexadecimal?
97d / 61h
19. In register byte order is what type of Endian?
big
20. In-memory byte order is in what type of Endian?
little
21. Motorola and IBM processors use(d) what type of Endian?
Big Endian
22. Intel/AMD uses what type of Endian?
little
23. True/False: Some processors are configurable (either in hardware or in software) to use either type of endianness
True, e.g. MIPS processor
24. What datatypes get switched around in little Endian?
multibyte: w, d, q, t
25. The RESX directive is very similar to the DX directive, but...
always specifies the number of memory elements

• e.g. L20    resw 100
• 100 uninitialized 2-byte words
• L20 is a pointer to the first word
26. What does this operation do:
add eax, ebx
eax = eax + ebx

Register: specifies one of the registers
27. What does this operation do:
add eax, [ebx]
eax = eax + content of memory at address ebx

Memory: specifies an address in memory
28. What does this operation do:
add eax, 2
eax = eax + 2

Immediate: specifies a fixed value (i.e. a number)
29. What does this operation do:
inc eax
eax = eax + 1

implied: not actually encoded in the instruction
30. What does this operation do:
mov dest, src
Moves data from the src location to the dest location
31. Which of the following is not okay:
A) mov eax, [ebx]
B) mov [eax], [ebx]
C) mov [eax], ebx
B) mov [eax], [ebx]

Because at most, one of the operands can be a memory operand. Both operands must be exactly the same size, which is not specified here.
(this multiple choice question has been scrambled)
32. what are the 5 size specifiers for moving immediate values to memory?
byte, word, dword, qword, tword

move dword [L], 1
33. How many bytes are moved?
mov [L1], 1
Error
34. How many bytes are moved?
move byte [L1], 1
1 byte
35. How many bytes are moved?
mov word [L1], 1
2 bytes
36. How many bytes are moved?
mov dword [L1], 1
4 bytes
37. How many bytes are moved?
mov [L1], eax
4 bytes
38. How many bytes are moved?
mov [L1], ax
2 bytes
39. How many bytes are moved?
mov [L1], al
1 byte
40. How many bytes are moved?
mov eax, [L1]
4 bytes
41. How many bytes are moved?
mov ax, [L1]
2 bytes
42. How many bytes are moved?
mov ax, 12
2 bytes
43. What does this command do?
mov eax, [L]
• - puts the contents of at address L into eax
• - puts 32-bits of content
44. What does this command do?
mov eax, L
• - puts the address L into eax
• - Puts the 32-bit address L into eax
45. What does this command do?
mov ebx, [eax]
puts the content at address stored in eax into ebx
46. What does this command do?
inc eax
increases eax by one
47. What does this command do?
mov ebx, [eax]
puts the contents at address stored in eax into ebx
 Author: tulipyoursweety ID: 315592 Card Set: Machine-Level & Systems Programming - Set 1 Updated: 2016-02-09 08:40:32 Tags: Assembly Folders: Machine-Level & Systems Programming Description: NASM: data and bss Show Answers: