I am getting the Exception thrown at 0x0044369D in Project2.exe: 0xC0000005: Access violation writing location 0x00000099. From my research so far, I am under the impression this has to do with a null pointer or out of range memory being accessed from the line `mov [eax], ecx`

I used the offset operator in `mov eax, OFFSET arrayfib`

and I thought that should remedy this. I can't seem to figure out what is causing the issue here.

```
.model flat, stdcall
.stack 4096
INCLUDE Irvine32.inc
ExitProcess PROTO, dwExitCode: DWORD
.data
arrayfib DWORD 35 DUP (99h)
.code
main PROC
mov eax, OFFSET arrayfib ;address of fibonacci number array
mov bx, 30 ;number of Fibonacci numbers to generate
call fibSequence ;call to Fibonacci sequence procedure
mov edx, OFFSET arrayfib ;passes information to call DumpMem
mov ecx, LENGTHOF arrayfib
mov ebx, TYPE arrayfib
call DumpMem
INVOKE ExitProcess, 0
main ENDP
;----------------------------------------------------------------------------------
;fibSequence
;Calculates the fibonacci numbers to the n'th fibonacci number
;Receives: eax = address of the Fibonacci number array
;bx = number of Fibonacci numbers to generate
;ecx = used for Fibonacci calculation (i-2)
;edx = used for Fibonacci calculation (i-1)
;returns: [eax+4i] = each value of fibonacci sequence in array, scaled for doubleword
;---------------------------------------------------------------------------------
fibSequence PROC
mov ecx, 0 ;initialize the registers with Fib(0) and Fib(1)
mov edx, 1
mov [eax], edx ;store first Fibonacci number in the array
;since a Fibonacci number has been generated, decrement the counter
;test for completion, proceed
mov eax, [eax+4]
fibLoop:
sub bx, 1
jz quit ;if bx = 0, jump to exit
add ecx, edx
push ecx ;save fib# for next iteration before it is destroyed
mov [eax], ecx ;stores new fibonacci number in the next address of array
push edx ;save other fib# before it is destroyed
mov ecx, edx
mov edx, [eax]
mov eax, [eax+4] ;increments accounting for doubleword
pop edx
pop ecx
quit:
exit
fibSequence ENDP
END main
```

Also if there are any other suggestions I would be happy to hear them. I am new to all this and looking to learn as much as possible.

asked on Stack Overflow Nov 2, 2019 by Madeline Do

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