exp_7_1.asm.svn-base

来自「单片机硬件实验代码」· SVN-BASE 代码 · 共 51 行

	    ORG         0000H 
	    LJMP        START
      	    ORG         0030H
	   
     START: MOV         30H,#40H   
	    MOV         31H,#50H
	    MOV         32H,#02H 
            MOV         R0,30H
            MOV         R1,31H
            MOV         R7,32H
    LOOP:  ACALL       ASCII_HEX
            SWAP        A                ;两个BCD码8位即可
            MOV         @R1,A
            INC         R0
            ACALL       ASCII_HEX
            XCHD        A,@R1
            INC         R0
            INC         R1
            DJNZ        R7,LOOP
            SJMP        $
            
   ;非法数据没进一步处理           
  ASCII_HEX: CLR         C       
             MOV         A,@R0
             SUBB        A,#30H
             CJNE        A,#0AH,_A
             AJMP        UPPER
        _A:  JC          DONE
      UPPER: SUBB        A,#11H                ;大写A-F
             CJNE        A,#06H,_B
             AJMP        LOWER
        _B:  JC          UP_LOW
      LOWER: SUBB        A,#20H                ;小写a-f   
             CJNE        A,#06H,_C
             AJMP        UP_LOW
       _C:   JC          UP_LOW
     UP_LOW: ADD         A,#0AH               
      DONE:  RET        
             
          END