Chapter-5 ARITHMETIC AND LOGIC INSTRUCTIONS

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ARITHMETIC AND LOGIC INSTRUCTIONS 1. Select an ADD instruction that will: (a) add BX to AX (b) add 12H to AL (c) add EDI and EBP (d) add 22H to CX (e) add the data addressed by SI to AL (f) add ... CX to the data stored at memory location FROG (g) add 234H to RCX A. (a) ADD AX,BX (b) ADD AL,12H (c) ADD EBP,EDI (d) ADD CX,22H (e) ADD AL,[SI] (f) ADD FROG,CX (g) ADD RCX,234H 2. What is wrong with the ADD RCX,AX instruction? A. You cannot use mixed-size registers 3. Is it possible to add CX to DS with the ADD instruction? A. No instruction is available to add to a segment register. 4. If and , list the sum and the contents of each flag register bit (C, A, S, Z, and O) after the ADD AX,DX instruction executes. A. AX = 3100H, C = 0, A = 1, S = 0, Z = 0, and O = 0 5. Develop a short sequence of instructions that adds AL, BL, CL, DL, and AH. Save the sum in the DH register. A. ADD AH,AL ADD AH,BL ADD AH,CL ADD AH,DL MOV DH,AH 6. Develop a short sequence of instructions that adds AX, BX, CX, DX, and SP. Save the sum in the DI register. A. ADD AX,BX ADD AX,CX ADD AX,DX ADD AX,SP 7. Develop a short sequence of instructions that adds ECX, EDX, and ESI. Save the sum in the EDI register. A. MOV EDI,ECX ADD EDI,EDX ADD EDI,ESI 8. Develop a short sequence of instructions that adds RCX, RDX, and RSI. Save the sum in the R12 register. A. MOV DI,AX MOV R12,RCX ADD R12,RDX ADD R12,RSI 9. Select an instruction that adds BX to DX, and also adds the contents of the carry flag (C) to the result. A. ADC DX,BX 10. Choose an instruction that adds 1 to the contents of the SP register. A. INC SP 11. What is wrong with the INC [BX] instruction? A. he instruction does not specify the size of the data addressed by BX and can be corrected with a BYTE PTR, WORD PTR, DWORD PTR, or QWORD PTR 12. Select a SUB instruction that will: [Show More]

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