;I\'m suppose to create a simple code in assembly where it would read a string f

Question

;I'm suppose to create a simple code in assembly where it would read a string from the user and swap the left and right of that string till it is completely in reverse order.

; (For Example: "Hello" to "olleH", "abcdef" to "fedcba", etc.)

;This is my code so far, could you let me know to configure the loop or what i'm missing/doing wrong.

INCLUDE Irvine32.inc

.data
MAX = 80
myString BYTE MAX+1 DUP (?)
myLength DWORD ?
numLoops DWORD ?

.code
Main PROC
call Clrscr

mov edx,OFFSET myString  ;buffer size -1
mov ecx,MAX
call ReadString
call StrLength  ;stores string length in eax

mov myLength,eax

xor edx,edx
mov ebx,2
div ebx

mov numLoops,eax
;ebx is left, edx is right, ecx current
mov ebx,OFFSET myString
mov edx,OFFSET myString
add edx,myLength
dec edx

mov ecx,numLoops

L1:
mov eax,0
mov al,[numLoops]
mov [eax],al
dec numLoops
inc eax
call WriteString
call Crlf

;inc ebx
;dec edx
loop L1
mov numLoops,OFFSET myString
mov ebx, 1
mov ecx, myLength-ebx
call DumpRegs
exit
main ENDP

END main

Explanation / Answer

You can use this code to print the reverse string of the given string.

Data Segment
str1 db 'String_Reverse','$'
strlen1 dw $-str1
strrev db 20 dup(' ')
Data Ends

Code Segment
Assume cs:code, ds:data
Begin:
    mov ax, data
    mov ds, ax
    mov es, ax
    mov cx, strlen1
    add cx, -2
    lea si, str1
    lea di, strrev
    add si, strlen1
    add si, -2
    L1:
       mov al, [si]
       mov [di], al
       dec si
       inc di
       loop L1
       mov al, [si]
       mov [di], al
       inc di
       mov dl, '$'
       mov [di], dl
    Print:
       mov ah, 09h
       lea dx, strrev
       int 21h
    Exit:
       mov ax, 4c00h
       int 21h
Code Ends
End Begin

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