MASM program

[Boyek]

UPPERCASE AND LOWERCASE..

.MODEL SMALL
.STACK 64
.DATA
;----------------------------------------------------------------------------
MSG DB 'bOYEk','$'
;----------------------------------------------------------------------------

.CODE
A10MAIN PROC FAR
MOV AX,@data ;initialize the segment
MOV DS,AX ;registers

MOV AH,09H
LEA DX,MSG
INT 21H

LEA BX,MSG
MOV CX,6 ;initialize to move 5 characters or the segment

A20: ;changing to lowercase
MOV AH,[BX]
CMP AH,41H
JA LOWERCASE
CMP AH,5AH
JA LOWERCASE
CMP AH,61H
JA LOWERCASE
CMP AH,7AH
JA LOWERCASE

LOWERCASE:
XOR AH,00100000B
MOV [BX],AH

A30:
INC BX ;increment next position
LOOP A20

MOV AH,09H ;display
LEA DX,MSG
INT 21H

MOV AX,4C00H
INT 21H ;terminate

A10MAIN ENDP
END A10MAIN