Issue comparing letters in a string [Assembly]

Question

I'm trying to create a program which iterates through a string and checks to see if it is a palindrome.

The word I am currently testing is racecar, but when I run the following code, it automatically decides that the first and last values aren't the same.

Is this just a case of entering the wrong registers into the loop, or is there something more than that?

main proc
mov edi, SIZEOF myWord- TYPE myWord ;length of string - type of data
mov ecx, LENGTHOF myWord/ 2  ;loop (N / 2) times
mov esi,OFFSET myWord ;beginning of string

checkWord:
mov al,[esi]
cmp [esi+edi],al
jne wordIsNotAPalindrome

add esi,TYPE myWord
sub edi,TYPE myWord
loop checkWord

mov edx, offset wordIsAPalindrome
call WriteString
exit
main endp

Declaration for myWord:

myWord BYTE "racecar", 0

Edit:

I just made a few adjustments, and this is what I have now:

main proc
mov edi, SIZEOF myWord- TYPE myWord
mov ecx, LENGTHOF myWord/ 2
mov esi,OFFSET myWord

checkWord:
mov al, SIZEOF myWord
mov al,[esi]
cmp [myWord+edi],al
jne wordIsNotAPalindrome

add esi,TYPE myWord
sub edi,TYPE myWord
loop checkWord

mov esi, offset wordIsAPalindrome
call WriteString
call Crlf
call Crlf
exit
main endp

It loops now correctly, and when I do Step Over, it proceeds to make it until wordIsAPalindrome. The problem is, this is the output:

Θµ#

Press any key to continue . . .

Answer 1

If you are using Irvine's WriteString, it takes the offset of the string from EDX register, not ESI, so :

     ▼
mov edx, offset wordIsAPalindrome
call WriteString