8-value moving average filter (Launchpad - temperature sensor demo code)

Hi,

can someone explain me how the 8-value moving average filter works? 8712.main.c.pdf

Thank you
Saretta 

/* Using an 8-value moving average filter on sampled ADC values */
long tempMeasured[8];
unsigned char tempMeasuredPosition=0;
long tempAverage;
long tempCalibrated, tempDifference; 

void ConfigureAdcTempSensor(void)
{
unsigned char i;
/* Configure ADC Temp Sensor Channel */
ADC10CTL1 = INCH_10 + ADC10DIV_3; // Temp Sensor, ADC10OSC/4 (ADC10SSEL = '00')
// VR+ = VREF+ and VR- = VSS, ADC10 sample-and-hold time = 64 × ADC10CLKs,
// Reference generator on, ADC10 on, ADC10 interrupt enable = ADC10IFG
// is set when conversion results are loaded into ADC10MEM
ADC10CTL0 = SREF_1 + ADC10SHT_3 + REFON + ADC10ON + ADC10IE;
__delay_cycles(1000); // Wait for ADC Ref to settle
ADC10CTL0 |= ENC + ADC10SC; // Enable conversion, Start conversion.
__bis_SR_register(CPUOFF + GIE); // LPM0 with interrupts enabled
tempCalibrated = ADC10MEM;
for (i=0; i < 8; i++)
tempMeasured[i] = tempCalibrated;
tempAverage = tempCalibrated;
}

/* Moving average filter out of 8 values to somewhat stabilize sampled ADC */
tempMeasured[tempMeasuredPosition++] = ADC10MEM;
if (tempMeasuredPosition == 8)
tempMeasuredPosition = 0;
tempAverage = 0;
for (i = 0; i < 8; i++)
tempAverage += tempMeasured[i];
tempAverage >>= 3; // Divide by 8 to get average