main.asm

从键盘输入一个字符串,先把它原样显示一遍 然后将其中的小写字母转换为大写显示,再将其中的大写字母转换为小写显示,最后将其中的大小写字母互换显示.显示字符串的功能调用采用宏,大写转换,小写转换和大小写互

       PRINT  MACRO
	
              LEA       DX,MSG2
              MOV       AH,09H
              INT       21H

              LEA       DX, STRS
              MOV       AH, 09H
              INT       21H
	
              LEA       DX,MESS
              MOV       AH,09H
              INT       21H

              LEA       DX,MSG3
              MOV       AH,09H
              INT       21H	

              LEA       DX, STRU
              MOV       AH, 09H
              INT       21H
	
              LEA       DX,MESS
              MOV       AH,09H
              INT       21H

              LEA       DX,MSG4
              MOV       AH,09H
              INT       21H     

              LEA       DX, STRL
              MOV       AH, 09H
              INT       21H
	
              LEA       DX,MESS
              MOV       AH,09H
              INT       21H

              LEA       DX,MSG5
              MOV       AH,09H
              INT       21H

              LEA       DX, STRE
              MOV       AH, 09H
              INT       21H
	
              ENDM

.MODEL        SMALL
.DATA
        MSG1  DB        'Please Insert:  ','$'
        MSG2  DB        'Your Insert:    ','$'
        MSG3  DB        'LowToUp:        ','$'
        MSG4  DB        'UpToLow:        ','$'
        MSG5  DB        'ChangeTwo:      ','$'
     STRSLEN  DB        20
      ACTLEN  DB        ?
        STRS  DB        20 DUP(?), '$'
        STRU  DB        20 DUP(0), '$'
        STRL  DB        20 DUP(0), '$'
        STRE  DB        20 DUP(0), '$'
        MESS  DB        0DH,0AH,'$'
;********************************************************************
.CODE
      EXTERN  TOUPPER:FAR, TOLOWER:FAR, ULCHG:FAR
	.startup
              LEA       DX,MSG1
              MOV       AH,09H
              INT       21H

              LEA       DX,STRSLEN
              MOV       AH,0AH
              INT       21H

              LEA       DX,MESS
              MOV       AH,09H
              INT       21H
    
              LEA       SI, STRS
              LEA       DI, STRU
              CALL      TOUPPER
	
              LEA       SI, STRS
              LEA       DI, STRL
              CALL      TOLOWER
	
              LEA       SI, STRS
              LEA       DI, STRE
              CALL      ULCHG
	
              PRINT
								
              MOV       AH, 4CH
              INT       21H
              END