docs: function encode() {
  		var p = [0, 0, 0, 0];
  
  		for (var i = 12; i >= 0; i--) {
  			var fb = codeword[i] ^ p[3];
  
  			p[3] = p[2] ^ gmult(30, fb);
  			p[2] = p[1] ^ gmult(6, fb);
  			p[1] = p[0] ^ gmult(9, fb);
  			p[0] = gmult(17, fb);
  		}
  
  		codeword[13] = p[0];
  		codeword[14] = p[1];
  		codeword[15] = p[2];
  		codeword[16] = p[3];
  	}