422.asm

微机原理与接口技术的部分课后题（十几题经典的）程序

DATA SEGMENT
 RBUF  DB 10H
       DB ?
       DB 10H DUP(?)
DATA ENDS
STACK SEGMENT PARA STACK
   DB 10H DUP(?)
STACK ENDS
CODE SEGMENT 
  ASSUME  CS:CODE,DS:DATA,ss:STACK      
START:MOV AX,DATA
      MOV DS,AX
      MOV SI,02H                 
      MOV DX,OFFSET RBUF 
      MOV AH,0AH
      INT 21H
      MOV DL,0AH              
      MOV AH,02H
      INT 21H
      MOV DL,0DH
      MOV AH,02H
      INT 21H
      MOV CX,3                               
      MOV DX,00H
L1:   MOV AL,RBUF[SI]       
      CALL CONV            
      OR  DL,AL            
      PUSH CX
      CMP CX,0
      JLE L2
      MOV CL,4
      SAL DX,CL            
      POP CX
      INC SI
      DEC CX
      JGE L1
L2:   MOV AX,DX            
      MOV CX,4
L3:   PUSH CX
      CMP CX,0
      JLE L4
      MOV CL,4
      ROL AX,CL
      MOV BL,AL
      CALL CONV_1     
      PUSH AX
      MOV DL,BL
      MOV AH,02H
      INT 21H
      POP AX
      POP CX
      DEC CX
      JGE L3
L4:   MOV AH,4CH
      INT 21H      
CONV   PROC
       PUSH CX
       AND AL,07FH          
       CMP AL,30H             
       JGE J1                 
       JMP J5
J1:    CMP AL,39H
       JG  J2
       SUB AL,30H   
       JMP J4
J2:    CMP AL,41H
       JGE J3
       JMP J5
J3:    CMP AL,46H
       JG J5
       SUB AL,37H
J4:    AND AL,0FH
J5:    POP CX
       RET
CONV   ENDP    
CONV_1 PROC
       PUSH CX
       AND BL,0FH
       CMP BL,09H       
       JLE J6
       ADD BL,07H       
J6:    ADD BL,30H
       POP CX
       RET
CONV_1 ENDP    
CODE ENDS
     END START