class GPIO {
	static Array gpio;
 
	function void init(int addr){
		let gpio = addr;
		return;
	}
  
	function boolean readBut() {
		if (gpio[1] & 2){
			return false;
		}
		return true;
   	}

   	function void writeLed(int c){
      		let gpio[0] = c;
		return;
   	}
   	
	function void readLed(){
      	return gpio[0];
   	}
	
}