Arduino Task Scheduling

/* run different tasks at different intervals on Arduino without
 * interrupts or blocking/delay
 */
void loop()
{
    int now = millis(); /* no sense in calling millis over and over */

    /* this runs at 1/10ms = 100Hz */
    if ( (now % 10) == 0) { /* short, frequent tasks at top */
        readGyro();
    }

    /* 1/50ms = 20Hz */
    if ( (now % 50) == 0) {
        readCompass();
    }

    /* this runs whenever there's a character available */
    /* possibly parsing GPS as well ala TinyGPS */
    if ( Serial.available() ) {
        readGPS();
    }

}