bitconv.pat

i need of vhdl code for 32-bit risc processor

in bit1 B;
in bit2 B;
in bit3 B;
out outvec (2 to 0) B;

begin
pat_0 :0 0 0 ?000;
pat_1 :0 1 0 ?010;
pat_2 :1 0 0 ?001;
pat_3 :1 1 1 ?111;

end;