求大神，以次代码略有不懂，求解释一下

CALLDOS MACRO FUNCTION    ;宏定义  CALLDOS                
        MOV AH,FUNCTION
        INT 21H
        ENDM 
                                         
CRLF MACRO    ;换行                                  
    MOV DL,0DH                              
    CALLDOS 2                               
	MOV DL,0AH                                    
	CALLDOS 2
	ENDM 

	                                          
DATA SEGMENT                                
	MESSAGE DB 'Please input 10 number:',0DH,0AH,'$'
	NUMBERS DB 10 DUP(?)           
	KB_BUF DB 3                    
	ACTLEN DB ?                    
	BUFFER DB 3 DUP(?)              ;输入的字符放在次区域中
	LE59 DB 0                        ;0——5的个数
	GE60 DB 0                        ;60——79的个数