Oracle character bitwise OR Function

/*
Function Name: Oracle character bitwise OR Function
Parameter constraints: the length of P1 and P2 must be consistent.
*/
Create or replace function f_bitor (p1 in string, P2 in string) return varchar2 is
Result varchar2 (16 );
T_p number (3 );
R_p varchar2 (16 );
P_P number (3 );
C_1 char (1 );
C_2 char (1 );
Begin
T_p: = length (P1 );
P_P: = 0;
Loop
-- Exit condition
Exit when P_P = t_p;
-- Value by bit
C_1: = substr (P1, P_P, 1 );
C_2: = substr (P2, P_P, 1 );
-- Assign values after comparison
If C_1> C_2 then
R_p: = R_p | to_char (C_1 );
Elsif C_1 <C_2 then
R_p: = R_p | C_2;
Else -- equal
R_p: = R_p | C_1;
End if;
-- Offset
P_P: = P_P + 1;
End loop;
Return (R_p );
End f_bitor;