Oracleで無理やりビット演算（And演算）

CREATE FUNCTION BITAND
(numSetNumber1 IN NUMBER
,numSetNumber2 IN NUMBER)
RETURN NUMBER IS
numResult     NUMBER;
numNumber1    NUMBER;
numNumber2    NUMBER;
numPoint      NUMBER;
BEGIN
--初期化
numNumber1    := numSetNumber1;
numNumber2    := numSetNumber2;
numPoint      := 1;
numResult     := 0;
-- ビット演算
WHILE ((numNumber1 != 0) AND (numNumber2 != 0))
LOOP
-- 余りを足した結果が２ならば、そのビットは１
IF (((numNumber1 MOD 2)+(numNumber2 MOD 2))=2) THEN
numResult := numResult + numPoint;
END IF;
-- 桁上げ
numNumber1 := TRUNC(numNumber1 / 2);
numNumber2 := TRUNC(numNumber2 / 2);
numPoint := numPoint * 2;
END LOOP;
--結果
RETURN(numResult);
END BITAND;