.586
.MODEL FLAT
INCLUDE io.h
.STACK 4096

.DATA
	; VARIOUS PROMPTS USED FOR USER INPUT/OUTPUT
		elementPrompt	BYTE	"[Negative cancels input] Enter element into array: ", 0
		string			BYTE    20 DUP (?)
		resultLbl		BYTE	"Array Information:", 0
		averageLbl		BYTE	"Average of", 0
		elementLbl		BYTE	"Elements:", 0
		outMsgLbl		BYTE	80 DUP (?)
		errorLbl		BYTE	"Zero input elements; program terminating", 0

	; VARIABLES USED FOR STORAGE AND CALCULATION
		numberElements	DWORD   11	DUP (?), 0
		numArray		DWORD	100	DUP	(?)
		arrayAvg		DWORD	11	DUP	(?), 0

EXTRN avg:PROC

.CODE
_MainProc PROC
	; INITIALIZE COUNT AND OBTAIN ARRAY ADDRESS:
		mov		numberElements, 0	; Initialize elements to 0
		lea		ebx, numArray		; Obtain address of array
	; WHILE LOOP FOR USER INPUT:
		whileLoop:
			input	elementPrompt, string, 20	; Prompt user
			atod	string						; Convert to double word
			cmp		eax, 0						; Test for negative number
			jl		endWhile					; If negative, exit loop
			mov		[ebx], eax					; Move number into array
			inc		numberElements				; Increment numberElements
			add		ebx, 4						; Obtain next address
			loop	whileLoop					; Continue loop
		endWhile:
	; TEST FOR 0 INPUT
		cmp		numberElements, 0		; Test for zero input
		jg		next					; If input, skip termination
		output	resultLbl, errorLbl		; If zero input, output error
		jmp		quit					; and terminate
	; PROCEED	
		next:
		lea		eax, numArray		; load array address
		push	eax					; push array onto stack
		lea		eax, numberElements	; load count address
		push	eax					; push count onto stack
		lea		eax, arrayAvg		; load average address
		push	eax					; push average onto stack
		
		call	avg			; call average
		
		; proceed with output
		;		..
		;		..
		;		etc
		
		
		
	; TERMINATE PROGRAM
		quit:
        mov     eax, 0			; exit with return code 0
        ret
_MainProc ENDP
END                             ; end of source code

.586
.MODEL FLAT
.CODE
avg		PROC
	push	ebp			; save register values
	mov		ebp, esp	; mov esp into ebp
	push	eax			; save register values
	push	ebx		
	push	ecx
	push	edx
	
	mov		eax, [ebp+8]	; obtain address of arrayAvg
	mov		edx, [ebp+12]	; obtain address of numberElements
	mov		ebx, [ebp+16]	; obtain address of numArray
	mov		ecx, edx		; move number of elements into count for looping
	mov		eax, 0			; Initialize average to 0
	
	forLoop:
		add		eax, [ebx]	; add current array element to eax -- ?UNHANDLED EXCEPTION?
		add		ebx, 4		; obtain next array value
		loop	forLoop		; loop, decrementing ecx
	div		edx			; divide eax (total) by number of elements
	push	eax			; push average onto the stack
		
	ret
avg		ENDP
END