Answer to Question #285654 in Assembler for byybo123

Question

Write an 8086 assembly language program that input characters string and prints them in reverse order. Use a stack.

HINT: Take user input with interrupt method in loop until user press Enter.

Answer 1

.stack 16h

DATA SEGMENT

msg1 db "String: $"

msg2 db 10,13, "String after revers: $"

DATA ENDS

CODE SEGMENT

START:

   MOV AX,DATA

   MOV DS,AX   

   MOV ES,AX

; print a message1:

   mov dx, offset msg1

   mov ah, 9

   int 21h

   xor cx,cx ; counter of characters

 wait_for_key:

; wait for any key press:

   mov ah, 0

   int 16h

;print charecter   

   mov    ah, 0eh

   int    10h

   push ax    ; save character to stack

   inc cx     ; counter++

; press 'Enter' to end:

   cmp    al, 13

   jz     _reverse    ; if press Enter

jmp    wait_for_key

;============================

_reverse:

 ; print a message2:

   mov dx, offset msg2

   mov ah, 9

   int 21h

; set cursor to next line

   mov   ah,2h

   mov dx, 200h

   int 10h

; print reverse

_print:    

    pop ax

    mov ah, 0eh

    int 10h

    dec cx

    cmp cx,0

    jnz _print  

  MOV AH,1         ; Waiting for a key press

   INT 16H   

EXIT_PROG:         ; Program is terminated

    MOV AH,4CH

    INT 21H

CODE ENDS

END START