问题详情

试求下列程序依次连续运行后有关单元中的内容。已知(20H)=24H,(24H)=BCH,SP=1FH,(1FH)=39H,(39H)=67H,外RAM(1000H)=10H,ROM(1010H)=FFH。
MOV A,1FH ;(1FH)→A,A=39H
MOV R0,20H ;(20H)+R0,R0=24H,
XCH A,39H ;A(39H) ,A=67H,(39H)=39H
PUSH Acc ;SP=20H,(20H)=67H
MOV DPTR,#1000H ;DPTR=1000H
MOVX A,@DPTR ;外RAM(1000H)→A,A=10H
MOVC A,@A+DPTR ;ROM (A+DPTR)=(1010H)→A,A=FFH
XCHD A,@R0 ;A_3～0(R0)_3～0,A=FCH,(24H)=BFH,R0=24H(不变)
POP 1FH ;(SP)=(20H)→1FH,(1FH)=67H,SP=1FH