TITLE     	PROG3-4  (EXE)   LOWERCASE TO UPPERCASE CONVERSION
   PAGE 	60,132
   .MODEL SMALL
   .STACK 64
   ;--------------
   		.DATA
   DATA1    	DB        	'mY NAME is jOe'
             	ORG	0020H
   DATA2  	DB        	14 DUP(?)
   ;--------------
   		.CODE
   MAIN      	PROC  	FAR
             	MOV 	AX,@DATA
             	MOV 	DS,AX
             	MOV 	SI,OFFSET DATA1	;SI points to original data
             	MOV 	BX,OFFSET DATA2	;BX points to uppercase data
             	MOV 	CX,14			;CX is loop counter
   BACK:     	MOV 	AL,[SI]			;get next character   
             	CMP 	AL,61H			;if less than 'a'           
                JB      OVER            ;then no need to convert
             	CMP  	AL,7AH 		;if greater than 'z'
                JA      OVER            ;then no need to convert 
             	AND  	AL,11011111B	;mask d5 to convert to uppercase
   OVER:     	MOV  	[BX],AL		;store uppercase character   
             	INC  	SI		;increment pointer to original 
             	INC  	BX		;increment pointer to uppercase data
             	LOOP 	BACK		;continue looping if CX > 0
             	MOV  	AH,4CH
             	INT  	21H		;go back to dos
   MAIN      	ENDP
               	END  	MAIN