Use call and ret instructions to convert lowercase words to uppercase

assume cs:code

data segment
	db 'conversation'
data ends

code segment

start:	mov ax, data
		mov ds, ax
		mov si, 0		;ds:si指向字符串（批量数据）所在空间的首地址
		
		mov cx, 12		;cx存放字符串的长度
		call capital	
		
		mov ax, 4C00H
		int 21H
		
capital:and byte ptr [si], 11011111B
		inc si
		loop capital
		ret
		
code ends
end start