汇编小写字符转变成大写

DATAS SEGMENT
    str db 100,0,101 dup('$')  
DATAS ENDS

STACKS SEGMENT
    DB   256 DUP(0)
    TOS  LABEL  WORD
STACKS ENDS


CODES SEGMENT
   
    ASSUME CS:CODES,DS:DATAS,SS:STACKS

START:
    MOV AX,DATAS
    MOV DS,AX
    
    LEA DX,str
    
    call input    ;输入字符串 
    
    call chage     ;小写字符转变成大写 
    
    call  disp    ;显示输出
    
    MOV AH,4CH
    INT 21H
    
chage proc near           ;小写字符转变成大写