TITLE Value Swap

; This program adds and subtracts 32-bit integers
; and stores the sum in a variable.

INCLUDE Irvine32.inc

.data
array DWORD 2,4,6,8
halfsize DWORD ? ; Half the size of our array, will be calculated later

.code
main PROC

	MOV edi, OFFSET array	; Address of array
	MOV ecx, LENGTHOF array / 2	; Loop counter -- Swapping 2 values takes 1/2 the size of the array (0.5 * n) iterations.


L1:
	MOV ebx, [edi]				; Grab element, put it into a register

	XCHG ebx, [edi+4]			; Exchange ebx element with next element in the array

	mov [edi], ebx				; Move ebx back into the array
	ADD	edi, 8					; Move to the next pair -- we need to increment twice here. Adding 8 because that = 8 bytes = 2 DWORDS


	loop L1						; Loop

	exit
main ENDP
END main