Backwards String

Posted on 2004-10-21
Medium Priority
Last Modified: 2008-03-03
I am trying to take a string from one variable and stick it into another variable backwards.  YES this is a school project, but I am stuck.  Here is my code.

; this program copies a string from one variale to another and displays the string backwards

INCLUDE Irvine32.inc


source BYTE "This is the source string", 0                ; orig string
target BYTE SIZEOF source DUP(0)                          ; backwards string

main PROC
  mov edx, OFFSET source
  call WriteString
  call Crlf
  mov ecx, SIZEOF target
  mov esi, 0
  movzx eax, source [esi]
  push eax
  inc esi
  mov ecx, SIZEOF target
  mov esi,0
  pop eax
  mov source[esi], al
  inc esi
  mov edx, OFFSET target
  call WriteString
  call Crlf
  mov esi, OFFSET target
  mov ebx, 1
  mov ecx, SIZEOF target-1
  call DumpMem
main ENDP
END main

when I run the program there is nothing in my target variable.  Can anyone help me??
Question by:dabrat
  • 2
LVL 11

Accepted Solution

dimitry earned 150 total points
ID: 12377269
You can try:
  pop eax
  mov target[esi], al  ; <-- it seems like you made copy/paste too quickly
  inc esi

Author Comment

ID: 12414728
I tried your code snippet that you suggested, it works but the first letter is null and it drops off the last letter completly.

Thanks for your help
LVL 11

Expert Comment

ID: 12414766
You need to do:
mov ecx, (SIZEOF target) - 1
  and you need to
mov target[esi], 0
  at the end

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