color1 := 0xFFFFF5
color2 := 0xFEFDFF 
 
Loop % 3 + (r := 0, x := color1 ^ color2) 
	b := (8 * (A_Index - 1)), (r += (x & 0xff << b) >> b) 

MsgBox % r

color1 := 0xFFFFF5
color2 := 0xFEFDFF

While (b := (8 * (A_Index - 1))) < 17
	r += ((color1 ^ color2) & 0xff << b) >> b  
	
MsgBox % r

color1 := 0xFFFFF5
color2 := 0xFEFDFF

VarSetCapacity(buff, 8)
NumPut(color2, NumPut(color1, buff, "UInt"), "UInt")
Loop 3
   diff += Abs(*(&buff + A_Index - 1) - *(&buff + A_Index + 3))
MsgBox, % diff