strrev.asm

String reversal. it reverses the given string.

;TITLE   REVERSE THE WORDS IN STRING
;INPUT TO THE PROGRAMME:- ANY SENTENCE OF 80 CHARACTERS
;OUTPUT OF THE PROGRAMME:-REVERSE OF INPUT

.MODEL SMALL
.STACK 100
.DATA 
        M1              DB 10,13, 'ENTER THE STRING:$'
        M2              DB 10,13, 'THE REVERSE STRING :$'
        BUFF            DB 80
                        DB 0
                        DB 80 DUP(0)
        COUNTER1        DW 0
        COUNTER2        DW 0

.CODE 
START:  MOV             AX,@DATA
	MOV		DS,AX

	MOV		AH,09H		; Display message M1.
	MOV		DX,OFFSET M1
	INT		21H

	MOV		AH,0AH
	LEA		DX,BUFF		; I/P the string.
	INT		21H

	MOV		AH,09H
	MOV		DX,OFFSET M2	; Display message M2
	INT		21H

	LEA		BX,BUFF

	INC		BX

	MOV		CH,00H		; Take character count in DI
	MOV		CL,BUFF + 1
	MOV		DI,CX

BACK:	MOV		DL,[BX + DI]	; Point to the last character
	MOV		AH,02H		; Get the character
	INT		21H		; Display the character

	DEC		DI		; Decrement count

	JNZ		BACK		; Repeat until count is 0

EXIT:   MOV             AH,4CH          ; Terminate Go to DOS prompt
	INT		21H
END     START
END