READ MACRO MSG
    MOV AH,0AH
    LEA DX,MSG
    INT 21H
ENDM
    
PRINT MACRO MSG
    MOV AH,09H
    LEA DX,MSG
    INT 21H
ENDM
    
DATA SEGMENT
    CR EQU 0DH
    LF EQU 0AH
    MSG1 DB "ENTER THE STRING IN LOWERCASE:$"
    MSG2 DB CR,LF,"THE UPPERCASE STRING IS :$"

BUFF DB 255
             DB 0
             DB 255 DUP ('$')
DATA ENDS

CODE SEGMENT
    ASSUME CS:CODE,DS:DATA
START:    MOV AX,DATA
    MOV DS,AX
    PRINT MSG1
    READ BUFF
    MOV SI,OFFSET BUFF+2
    MOV CL,BYTEPTR[SI-1]
    MOV CH,00H

LP1:    MOV AH,[SI]
    MOV AL,61H
JB LP1
    CMP AL,7BH
    JNB LP1
    SUB AL,20H
    MOV [SI],AL

LP2:
    INC SI
    LOOP SP1
    PRINT MSG2
    PRINT MSG2
    PRINT BUFF+2
    MOV AH,4CH
    INT 21H
CODE ENDS
END START