xorgate.pat

i need of vhdl code for 32-bit risc processor

in a1 B;
in b1 B;
in c1 B;
out d1 B;

begin
pat_0 :0 0 0 ?0;
pat_1 :0 0 1 ?1;
pat_2 :0 1 0 ?1;
pat_3 :1 1 1 ?1;

end;