Insertion sort in Assembly - sorting

Question

So I'm coding out an insertion sort (in assembly) based on this high level code:
void insertionSort(int data[ ], int arraySize) {
int insert;
int moveItem;
for(int next=1; next<arraySize; next++) {
insert=data[next]; //store the value in the current element
moveItem=next; //initialize location to place element
while((moveItem>0)&&(data[moveItem-1]>insert)) {
//shift element one slot to the right
data[moveItem]=data[moveItem-1];
moveItem--;
} //end while
data[moveItem]=insert;
} //end for
} //end insertionSort
There are exactly 20 random numbers in an array called myArray. I cannot use an of the decision derivatives that come in the library that comes with our book. So basically movs, cmps, loops, and jumps
Here's what I got. I had it sorting the first of 20 random numbers earlier, but I've confused myself to death and have no idea what I'm doing any more. It crashes when it gets to the insertion sort method. Help please.
TITLE Insertion Sort (main.asm)
INCLUDE Irvine32.inc
.data
elems = 20
myArray sdword elems dup(0)
str1 byte "Press enter" ,0
str2 byte "The array now is ",0
next sdword 1
start sdword ?
.code
main PROC
call Clrscr
call CreateRandom
call Display
call InsertionSort
call Display
exit
main ENDP
CreateRandom PROC
;;;;Creates 20 random numbers and populates myArray;;;;;
call Randomize
mov ecx, 20
mov edx, OFFSET myArray
L1:
call Random32 ;create random number
mov [edx], eax ; move random number to the appropriate spot in the array
add edx, 4 ; increase the address of what it is pointing to
loop L1
mov edx, OFFSET str1 ; "press enter to continue"
call WriteString
call ReadInt
call Crlf
ret
CreateRandom ENDP
Display PROC
;;;; Displays current form of the array myArray;;;;;
mov edx, OFFSET str2 ; "The array now is:"
call WriteString ; write string
call Crlf
mov esi, OFFSET myArray ; offset of the array
mov ecx, 20 ; index of the loop
L2:
mov eax, [esi] ; move array at that point to eax
call WriteDec ; print out the array as a decimal
call Crlf ; next line
add esi, 4 ; next element in the array
loop L2
call Crlf
ret
Display ENDP
InsertionSort PROC
mov ecx, 19
mov edx, OFFSET myArray
mov ebx, OFFSET myArray ; eax=next
add ebx, 4 ;moves up the array to second element comparable to next
outterloop:
mov esi, [ebx] ; esi=data[next]
mov eax, ebx ;movelterm=ebx
L1:
mov edx, [eax-4] ;move the number that is greater into edx
mov [eax], edx ;move the number into that 2nd element of the
sub eax, 4
mov esi, [eax]
cmp eax, [edx]
JNG endinner ; if the address is not greater than the first address, skip to the end
mov edx, [eax-4]
cmp edx, esi ; if the address is greater, than it already sorted, skip to end
JG endinner
loop L1
endinner:
mov [eax], esi ; move first to the second to finish the sort
add ebx, 4 ;move to the next element of the array
inc next ;counting outside loop
cmp ecx, next
JNE outterloop ;return to top of for loop
ret
InsertionSort ENDP
END main

Answer 1

I haven't examined your code in detail, but I notice that InsertionSort seems to be using edx for two different purposes at once: as a pointer into the array, and to hold one of the values from the array. This will certainly break even if nothing else is wrong.
So, at the start of InsertionSort you say mov edx, OFFSET myArray -- it's a pointer into the array. Then, a few lines later, mov edx, [eax-4] -- oops, no, it's a value from the array. And a few lines later again, cmp eax, [edx] -- oh, no, now it's a pointer into the array again.
Perhaps that last instruction should be cmp edx, [eax] or something? Because eax does seem to be a pointer into the array here.