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Computer Architecture and Assembly Language – Midterm 2011 1. In instruction ADC the operands can be oTwo register only oTwo register and one memory location oCF and two other operands oZF and two other operands 2. After the execution of instruction “RET” oSP is incremented by 2 oSP is decremented by 2 oSP is incremented by 1 oSP is decremented by 1 3. The extended ASCII has o64 characters o128 characters o256 characters o502 characters 4. The second byte in the word designated for screen location holds oThe dimension of the screen oCharacter position on the screen Character color on the screen oACSII code of the character 5. REP will always oIncremented CX by 1 oIncremented CX by 2 oDecremented CX by 1 oDecremented CX by 2 6. The routine that executes in response to an INT instruction is called oISR oIRS oISP oIRT 7. The iAPX888 architecture consists of _______ register. o12 o14 o16 o18 8. In the instruction “CMP AX,BX” the contents of oAX are changed oBX are changed not conformed oCX are changed oFlag register are changed 9. All the addressing mechanisms iniAPX88 return a number called ______ address. oeffective ofaulty oindirect odirect 10.

The execution of the instruction “mov word [ES: DI], 0x0720” owill clear next character on screen owill print “20” at top left of the screen owill print “20” at top right of the screen owill move DI at location 0720 on the screen 11. “mov byte [num1],5” is _______ instruction. olegal oillegal ostack based omemory indirect 12. MOV instruction transfers a byte or word from which of the following source location. oDS:DI oES:SI oES:DI oDS:SI 13. The execution of the instruction “mov word [ES: 0], 0x0741” will print “A” on the screen, color of the character will be oBlack oWhite oRed oBlue 14.

If AX contains FFFFh, then after execution of instruction “SAL ax, 3”, the result will be o-3 o+3 o-8 o+8 15. If the decimal number “35” is shifted by two bit to left, the new value will be o35 o70 o140 o17 16. While using STOBS, if DF=1 then oThe value of SI will be incremented by one oThe value of SI will be incremented by two oThe value of SI will be decremented by one oThe value of SI will be decremented by two 17. After the execution of STOSW, the CX will be oDecremented by 1 oDecremented by 2 oIncremented by 1 oIncremented by 2 18. The memory address always move from oprocessor to memory memory to processor omemory to peripheral operipheral to processor 19. An offset alone is not complete without osegment ocode label oindex register odata label 20. Code Segment is associated to _______ register by default. oIP oSS oBP oCX 21. Write down the procedure to clear the selective bit. (Marks: 2) 22. Why REP prefix is generally not used with LODS instruction? (Marks: 2) 23. What is difference between REPE and REPNE? (Marks: 3) 24. Describe Push and Pop with the help of an example. (Marks: 3) 25. Explain all characteristics of SCAS instruction. (Marks: 5) 26. Describe Local Variable? (Marks: 5)