.MODEL SMALL
.DATA
msg1 DB "Please enter a string :",13,10,"$"
msg2 DB 13,10,"In lower case :",13,10,"$"
msg3 DB 13,10,"Press any key to continue.",13,10,"$"
str1 DB 80
strlen DB ?
chars DB 80 DUP(?)
.CODE
.STARTUP
MOV AH, 9
LEA DX, msg1
INT 21h
loop_1:
MOV AH, 0ah
LEA DX, str1
INT 21h
MOV CL, strlen
CMP CL, 0
JZ loop_1
MOV CH, 0
LEA SI, chars
loop_2:
MOV AL, DS:[SI]
CMP AL, "A"
JB next_1
CMP AL, "Z"
JA next_1
ADD AL, 32
MOV DS:[SI], AL
next_1:
INC SI
LOOP loop_2
MOV BYTE PTR DS:[SI], "$"
MOV AH, 9
LEA DX, msg2
INT 21h
LEA DX, chars
INT 21h
MOV AH, 9
LEA DX, msg3
INT 21h
MOV AX, 0c08h
INT 21h
.EXIT
.STACK
END