Printing Out a String Stored in an Array of DWORDS - arrays

Question

I'm writing a program in Assembly that will Bubble Sort an Array of Strings. A zero length string terminates the array. I approached this by declaring a DWORD array, where the string var., that is a byte size, shall be stored. My main problem is not the bubble sort itself, but that strings that were stored in the array wasn't outputting completely.
To hopefully make it clear, here is my code:
.586
.MODEL FLAT
INCLUDE io.h ; header file for input/output
space equ 0
cr equ 0dh
.STACK 4096
.DATA
myStrings byte "Delts",0
byte "Abs",0
byte "Biceps",0
byte 0
labelStrOut byte "Output is: ", 0
stringOut dword 11 dup (?)
stringNum dword 0
stringArray dword 20 dup (?)
.CODE
_MainProc PROC
mov edi, offset myStrings
mov esi, offset stringArray
popltLp:
cmp BYTE PTR [edi], 0
jz popltDone
mov ebx, [edi]
mov DWORD PTR [esi], ebx
add esi, 4
inc stringNum
xor ecx, ecx
not ecx
xor al, al
repne scasb
jmp popltLp
popltDone:
xor edx, edx
lea esi, stringArray
mov ebx, DWORD PTR [esi]
mov stringOut, ebx
output labelStrOut, stringOut
add esi, 4
mov ebx, DWORD PTR [esi]
mov stringOut, ebx
output labelStrOut, stringOut
add esi, 4
mov ebx, DWORD PTR [esi]
mov stringOut, ebx
output labelStrOut, stringOut
outptDone:
mov eax, 0 ; exit with return code 0
ret
_MainProc ENDP
END ; end of source code
As can be seen, no Bubble Sorting is being done yet...
The lines below 'popltDone' is just me messing around to see if the strings carried over to the array just fine. However, when printed out on the screen, only 4 characters were just showing up! The entire string line was just not being printed out, which is currently driving me crazy. Can someone please tell me what I am doing wrong?
Thanks to anybody taking the time reading this.

Answer 1

The problem is, you aren't using string pointers correctly. Specifically, here's the code I'm referring to:
mov ebx, [edi]
mov DWORD PTR [esi], ebx
If you were to translate this into English, it would be something like this:
Move the 4 byte value pointed to by edi into ebx.
Move the value in ebx into the memory address pointed to by esi.
This is perfectly legal and may actually be what you want in some cases, but I'm guess this isn't one of them. The reason you are only seeing the first 4 characters when you output your array of strings is because you copied the literal string into your array. A DWORD is 4 bytes so you get the first 4 characters. Here's what I would write:
mov DWORD PTR [esi], edi
Which translates into:
Move the pointer value edi into the memory address pointed to by esi.
Now you have not an array of strings, but an array of string pointers. If you were to write your code in C, decompile it, this is most likely what you would see. Rewrite your comparison and output functions to work with the pointer to a string instead of the literal characters in the string and you'll fix your problem.