A4 Sample Solution Ch3

Transcription

1 A4 Sample Solution Ch3 2. AL, AH, BL, BH,CL,CH,DLl, DH 3. AX, BX, CX, DX, SP, BP, SI, DI, CS, DS, ES, SS, FS, GS 4. EAX, EBX, ECX, EDX, ESP, EBP, EDI, ESI 5. RAX, RBX, RCX, RDX, RSP, RBP, RSI, RDI and R8 R15 6. CS, DS, ES, SS, FS, GS 7. The register sizes must be equal, 16-bit cannot be fit into 8-bits 8. Register sizes should be the same 9(f). MOV R10,R8 10(d). MOV RAX, 1000H 12. chooses a model that is only one segment. Thismodel is faster and can be compiled to a.com file (instead of.exe) 13..CODE 15. Opcode 16. Any English alphabet letters, and special characters such -, $, and? 17. It ends the program by exiting to the operating system 18. No. An assembler translates a program in the tiny model to a.com 19. The.STARTUP directive loads the DS register 20. A displacement is the distance from the beginning of a segment. In that command, 2000H will be added to the content of DS times 10H 21. Indirect addressing H 27. DEC QWORD PTR [RAX] 28. The first one copies to BX the content of the memory from the location that its displacement is DATA, the second one copies to BX the displacement. 29(b) H 30. nothing 31(c) H 32(c) H 33(c) H 35(b) H 36. FIELDS STRUCT F1 DW? F2 DW? F3 DW? F4 DW? F5 DW? FIELDS ENDS 37. FIELDS+8 38.Direct, relative, indirect 39. 5, the first byte is the opcode, followed by a two byte segment address, followed by a two byte offset address 40. by the former, one can jump to anywhere in memory; by the latter, one can jump only within the current code segment. 41. ±32K

2 A far jump always a jump to any location in the memory map 44. short 45. (a) short (b) near (c) short (d) far 46. JMP BX 47. JMP NEAR PUSH [DI] places the 16-bit contents of the location addressed by DS and DI onto the stack. 50. AX, CX, DX, BX, SP, BP, SI, DI 51. Places the 32-bit contents of the register array onto the stack 52. PUSHFD 53. no Ch4 5. If operated in the 16-bit mode, a register-size and/or address-size prefix is used to specify a 32-bit register. 7. (a) SS (b) DS (c) DS (d) SS (e) DS 9. MOV BX,[BP+4C00H] 10. 8b in the flat mode, it allows the 64-bit registers to be addressed in this instruction PUSH RAX 17. CS 19. EAX, EBX, ECX, EDX, ESP, EBP, EDI and ESI 20. a) push ax to the stack; b) pop the32-bit content of top of the stack to ESI c) push the content of the memory that its displacement is in BX onto the stack d) push all flags onto the stack e) pop the top of the stack to DS and f) push a 32-bit number 4 on to the stack There are many. one of them is SP=0200H SS=0200H 25. The MOV DI,NUMB instruction copies the 16-bit number in the data segment location NUMB into DI while the LEA DI,NUMB loads DI with the offset address of location NUMB. 26. both do the same; but the latter is faster. 27. The MOV with the OFFSET directive 28. BX will be loaded from the memory location (displacement) NUMB and DS will be loaded from that location +2 (ie. NUM+2) 29. LDS loads DS and LSS loads SS along with another 16-bti register for the offset address 30. MOV BX, NUMB MOV DX,BX MOV SI,DX 33. MOVS 36. Sends the string located at DS+SI to the IO device that its address is in DX. Also, SI will be updated based on the content of flag D/ 38. MOV SI, OFFSET SOURCE MOV DI, OFFSET DEST MOV CX, 12

3 REP MOVSB 39. The REP prefix repeats a string instruction CX number of times. 40. XCHG EBX, ESI 41. DX register 43. TABLE DB 30H, 31H, 32H, 33H DB 34H, 35H, 36H, 37H, 38H, 39H BCD2A PROC NEAR MOV BX,OFFSET TABLE XLAT BCD2A ENDP 45. IN AL, 12H copies the byte from I/0 device 12H into AL 46. Copies content of AX to the memory location DS+DX 47. The segment override prefix allows the default segment to be changed to any segment 50. It s a special command to the assembler 51. DX is copied into CX if a not zero or not equal condition exists. 53. LIST1 DB 30 dup(?) The.686 directive informs the assembler that a Pentium Pro or newer microprocessor is the target of the assembled program. 56. it specifies the type of memory model used by the program 57. models 58. full segment definition 59. The program terminates and control is passed back to the operating system. 61. The uses directive specifies which registers are saved on the stack at the beginning of a procedure and popped at the end of the procedure. 62.STORE PROC NEAR MOV [DI],AL MOV [DI+1],AL MOV [DI+2],AL MOV [DI+3],al COPY ENDP 63. If the model statement precedes the processor directive the code generated is 16-bit. 64. COPY PROC FAR MOV AX,CS:DATA4 MOV BX,AX MOV CX,AX MOV DX,AX MOV SI,AX COPY ENDP Ch5 1(f) ADD FROG,CX 3. No instruction is available to add to a segment register. 6. ADD AX,BX

4 ADD AX,CX ADD AX,DX ADD AX,SP 7. MOV EDI,ECX ADD EDI,EDX ADD EDI,ESI 10. INC SP 12. a) SUB CS,BX b) SUB DH,OEEH c) SUB SI,DI d) SUB EBP,3322H e) SUB CH,[SI] f) SUB DX,[SI+10] g) SUB FROG,AL h) SUB R10,R9 13. DL = 81H, S = 1, Z = 0, C = 0, A = 0, P = 0, O = AH and AL 19. AH contains the most significant part of the result and AL contains the least significant part of the result. 20. the O and C flags contain the state of the most significant portion of the product. 22. MOV DL, 5 MOV AL, DL MUL DL MUL DL 25. AX 26. AX 31. RAX 37. PUSH AX MOV AL,BL ADD AL,DL MOV AL,BH ADC AL,DH MOV BX,AX POP AX ADC AL,CL XCHG AH,AL ADC AL,CH XCHG AH,AL 39(f). AND DX,[SI 8] 40. MOV BH,DH AND BH,1FH 41(b) OR ECX,88H 42.MOV SI,DI OR, SI, 1FH 43(f). XOR DI,[BP+60]

5 44. OR AX,0FH AND AX,1FFH XOR AX,0380H 47. NOT is one s complement and NEG is two s complement. 48(c). 50. Extra 55. MOV DI,OFFSET LIST MOV CX,300H CLD MOV AL,66H REPNE SCASB 56. In DOS mode, Letter C is printed