Capital

assume cs:code, ds:data

data segment

    db 'hello world'
    
data ends

code segment
    
    start: mov ax, data
           mov ds, ax
           mov bx, 0
            
           mov cx, 11
           
           call capital
           mov ax, 4C00H
           int 21H
           
    capital: and byte ptr [bx], 11011111B
             inc bx
             loop capital
             ret

code ends

end start