------------------------------------------------------------------------------
-- GCD factorization Benchmark
------------------------------------------------------------------------------

entity GCD is 
 port (CLK            : in bit;
       Reset          : in bit;
       X, Y           : in integer range 0 to 65535;
       gcd_output     : out integer range 0 to 65535);
end GCD;

------------------------------------------------------------------------------
architecture rtl of GCD is 
begin 
BIGLOOP: process
variable xvar,yvar :  integer range 0 to 65535;
begin
  RESET_LOOP : loop
      wait until CLK = '1'; 
      xvar := X;
      yvar := Y;
      if ((xvar = 0) or (yvar = 0) or (Reset = '1')) then
          gcd_output <= 0;
          xvar := 0;
          yvar := 0;
      else
        COMP: loop
          wait until CLK = '1'; 
          exit RESET_LOOP when (Reset = '1');
          if (xvar < yvar) then 
              yvar := yvar - xvar;
          else 
              if (xvar > yvar) then  
                  xvar := xvar - yvar;
              end if;
          end if;
          exit COMP when (xvar = yvar); 
        end loop COMP;
        gcd_output <= xvar;
      end if;
  end loop RESET_LOOP;
end process;

end rtl;