题目内容

()=F0H, (R0)=30H, and (30H)=AAH. After execution of an instruction XCH A, @R0, accumulator will be,( )

AAH
B. F0H
C. 30H
D. 78H

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()=F0H, (R1)=40H, and (40H)=0FH. After execution of an instruction XCHD A, @R1, accumulator will be,( )

A. 00H
B. F0H
C. 0FH
D. FFH

Instruction “MOV A, @R1” will ( )

A. copy R1 to the accumulator
B. copy the accumulator to R1
C. copy the contents of internal RAM pointed by R1 to accumulator
D. copy the contents of external RAM pointed by R1 to accumulator

Which of the following instruction will move the number 27H in the accumulator? ( )

A. MOV A, 27
B. MOV A, #27H
C. MOV A, 27H
D. MOV A, @27

Which of the following is invalid instruction? ( )

A. MOVX R0, @DPTR
B. MOVC A, @A+PC
C. XCH A, 10H
D. XCH A, @R1

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