关于单片机的两道题.1.已知程序执行前有A=02H,SP=5-查字典问答网
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  关于单片机的两道题.1.已知程序执行前有A=02H,SP=52H,(51H)=0FFH,(52H)=0FFH.下述程序执行后:POPDPHPOPDPLMOVDPTR,#4000HRLAMOVB,AMOVCA,@A+DPTRPUSHAMOVA,BINCAMOVCA,@A+DPTRPUSHARETORG4000HDB10H,80H,30H,50H,30H,50H请

  关于单片机的两道题.

  1.已知程序执行前有A=02H,SP=52H,(51H)=0FFH,(52H)=0FFH.下述程序执行后:

  POPDPH

  POPDPL

  MOVDPTR,#4000H

  RLA

  MOVB,A

  MOVCA,@A+DPTR

  PUSHA

  MOVA,B

  INCA

  MOVCA,@A+DPTR

  PUSHA

  RET

  ORG4000H

  DB10H,80H,30H,50H,30H,50H

  请问:(A)=(),(SP)=(),(51H)=(),(52H)=(),(PC)=().

  2.程序段如下,试说明其功能.

  MOVR0,#50H

  MOVR1,#60H

  MOVA,@R0

  ADDA,@R1

  MOV@R0,A

  INCR0

  INCR1

  MOVA,@R0

  ADDCA,@R1

  MOV@R0,A

  MOV00H,C

1回答
2020-12-27 05:08
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  (1)

  A=02H,SP=52H,(51H)=0FFH,(52H)=0FFH.POPDPH;SP=51H

  POPDPL;SP=50H

  MOVDPTR,#4000H

  RLA;A=04H

  MOVB,A;B=04H

  MOVCA,@A+DPTR;A=30H

  PUSHA;SP=51H;(50H)=30H

  MOVA,B;A=04H

  INCA;A=05H

  MOVCA,@A+DPTR;A=50H

  PUSHA;SP=52H;(51H)=50H

  RET;PC=5030H

  ORG4000H

  DB10H,80H,30H,50H,30H,50H

  请问:(A)=(50H),(SP)=(52H),(51H)=(50H),(52H)=(FFH),(PC)=(5030H).

  (2)把位于51H、50H(51H是高字节)和61H、60H(61H是高字节)的两个双字节数相加,结果存回51H、50H.

2020-12-27 05:09:05

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