QUESTIONS AND PROBLEMS
1. What do the following MOV instructions accomplish?
(a) MOV AX,BX
(b) MOV BX,AX
(c) MOV BL,CH
(d) MOV ESP,EBP
(e) MOV RAX,RCX
2. List the 8-bit registers that are used for register addressing.
3. List the 16-bit registers that are used for register addressing.
4. List the 32-bit registers that are used for register addressing in the 80386 through the Core2 microprocessors.
5. List the 64-bit registers available to the 64-bit mode of the Pentium 4 and Core2.
6. List the 16-bit segment registers used with register addressing by MOV, PUSH, and POP.
7. What is wrong with the MOV BL,CX instruction?
8. What is wrong with the MOV DS,SS instruction?
9. Select an instruction for each of the following tasks:
(a) copy EBX into EDX
(b) copy BL into CL
(c) copy SI into BX
(d) copy DS into AX
(e) copy AL into AH
(f) copy R8 into R10
10. Select an instruction for each of the following tasks:
(a) move 12H into AL
(b) move 123AH into AX
(c) move 0CDH into CL
(d) move 1000H into RAX
(e) move 1200A2H into EBX
11. What special symbol is sometimes used to denote immediate data?
12. What is the purpose of the .MODEL TINY statement?
13. What assembly language directive indicates the start of the CODE segment?
14. What is a label?
15. The MOV instruction is placed in what field of a statement?
16. A label may begin with what characters?
17. What is the purpose of the .EXIT directive?
18. Does the .MODEL TINY statement cause a program to assemble as an execute (.EXE) program?
19. What tasks does the .STARTUP directive accomplish in the small memory model?
20. What is a displacement? How does it determine the memory address in a MOV DS:[2000H],AL instruction?
21. What do the symbols [ ] indicate?
22. Suppose that DS = 0200H, BX = 0300H, and DI = 400H. Determine the memory address accessed by each of the following instructions, assuming real mode operation:
(a) MOV AL,[1234H]
(b) MOV EAX,[BX]
(c) MOV [DI],AL
23. What is wrong with a MOV [BX],[DI] instruction?
24. Choose an instruction that requires BYTE PTR.
25. Choose an instruction that requires WORD PTR.
26. Choose an instruction that requires DWORD PTR.
27. Select an instruction that requires QWORD PTR.
28. Explain the difference between the MOV BX,DATA instruction and the MOV BX,OFFSET DATA instruction.
29. Suppose that DS = 1000H, SS = 2000H, BP = 1000H, and DI = 0100H. Determine the memory address accessed by each of the following instructions, assuming real mode operation:
(a) MOV AL,[BP + DI]
(b) MOV CX,[DI]
(c) MOV EDX,[BP]
30. What, if anything, is wrong with a MOV AL,[BX][SI] instruction?
31. Suppose that DS = 1200H, BX = 0100H, and SI = 0250H. Determine the address accessed by each of the following instructions, assuming real mode operation:
(a) MOV [100H],DL
(b) MOV [SI + 100H],EAX
(c) MOV DL,[BX + 100H]
32. Suppose that DS = 1100H, BX = 0200H, LIST = 0250H, and SI = 0500H. Determine the address accessed by each of the following instructions, assuming real mode operation:
(a) MOV LIST[SI],EDX
(b) MOV CL,LIST[BX + SI]
(c) MOV CH,[BX + SI]
33. Suppose that DS = 1300H, SS = 1400H, BP = 1500H, and SI = 0100H. Determine the address accessed by each of the following instructions, assuming real mode operation:
(a) MOV EAX,[BP + 200H]
(b) MOV AL,[BP + SI – 200H]
(c) MOV AL,[SI – 0100H]
34. Which base register addresses data in the stack segment?
35. Suppose that EAX = 00001000H, EBX = 00002000H, and DS = 0010H. Determine the addresses accessed by the following instructions, assuming real mode operation:
(a) MOV ECX,[EAX + EBX]
(b) MOV [EAX + 2*EBX],CL
(c) MOV DH,[EBX + 4*EAX + 1000H]
36. Develop a data structure that has five fields of one word each named Fl, F2, F3, F4, and F5 with a structure name of FIELDS.
37. Show how field F3 of the data structure constructed in question 36 is addressed in a program.
38. What are the three program memory-addressing modes?
39. How many bytes of memory store a far direct jump instruction? What is stored in each of the bytes?
40. What is the difference between an intersegment and intrasegment jump?
41. If a near jump uses a signed 16-bit displacement, how can it jump to any memory location within the current code segment?
42. The 80386 and above use a -bit displacement to jump to any location within the 4G-byte code segment.
43. What is a far jump?
44. If a JMP instruction is stored at memory location 100H within the current code segment, it cannot be a jump if it is jumping to memory location 200H within the current code segment.
45. Show which JMP instruction assembles (short, near, or far) if the JMP THERE instruction is stored at memory address 10000H and the address of THERE is:
(a) l0020H
(b) 11000H
(c) 0FFFEH
(d) 30000H
46. Form a JMP instruction that jumps to the address pointed to by the BX register.
47. Select a JMP instruction that jumps to the location stored in memory at the location TABLE. Assume that it is a near JMP.
48. How many bytes are stored on the stack by a PUSH AX?
49. Explain how the PUSH [DI] instruction functions.
50. What registers are placed on the stack by the PUSHA instruction? In what order?
51. What does the PUSHAD instruction accomplish?
52. Which instruction places the EFLAGS on the stack in the Pentium 4 microprocessor?
53. Is a PUSHA available in the 64-bit mode of the Pentium 4 or the Core2?