PIC microcontroller digital tube program

   ORG  000H
   GOTO A1
   ORG  0CH
A1 MOVLW 1; bit 1 displays the number
   MOVWF 50H; 
   MOVLW 2; bit 2 displays the number
   MOVWF 51H;
   MOVLW 3; bit 3 displays the number
   MOVWF 52H;
   MOVLW 4; bit 4 displays the number
   MOVWF 53H;
   MOVLW 4; Display digits
   MOVWF 40H;
   MOVLW B'00000001'; bit code
   MOVWF 41H;
   MOVLW 50H;
   MOVWF FSR ; indirect addressing
   
A2 BSF STATUS,RP0;body1
   BCF  STATUS,RP1;
   MOVLW 0;
   MOVWF TRISB; RB port is set as output port
   MOVWF TRISD; RD port is set as output port
   BCF STATUS,RP0;body0
   BCF  STATUS,RP1;
   MOVLW 0FFH;
   MOVWF PORTB; RB port outputs high level
   MOVLW 0
   MOVWF PORTD; RD port outputs low level to clear the screen
   
   MOVFW INDF; indirect addressing display data  
   CALL Q1; check the data table
   MOVWF PORTB; Display the broken code output to port RB
   INCF FSR,1; Indirect addressing address plus 1
   MOVFW 41H ; bit code
   MOVWF PORTD; bit code output to RD port
   RLF 41H,0; Process C
   RLF 41H,1; left shift code
   CALL M001; Delay
   DECFSZ 40H,1; Determine whether the 4 bits are displayed
   GOTO A2; otherwise continue to display
   GOTO A1; is to return
;*********************************************
; Delay subroutine
;*********************************************
M001
   MOVLW 2
   MOVWF 30H
M002  MOVLW 250
   MOVWF 31H
   DECFSZ 31H,1
   GOTO $-1
   DECFSZ 30H, 1
   GOTO M002
   RETURN
;********************************************
; data sheet
;********************************************      
Q1   ADDWF  PCL,1  
    RETLW     00C0H        ;0
       RETLW     00F9H        ;1
        RETLW     00A4H        ;2
        RETLW     00B0H        ;3
      RETLW     0099H        ;4
      RETLW     0092H        ;5
      RETLW     0082H        ;6
      RETLW     00F8H        ;7
      RETLW     0080H        ;8
      RETLW     0090H        ;9
      RETLW     0088H        ;A
      RETLW     0083H        ;B
      RETLW     00C6H        ;C
      RETLW     00A1H        ;D
      RETLW     0086H        ;E
      RETLW     008EH        ;F
   END