Exercice en classe pour calcul du plus grand commun diviseur

gcd.vhd

library IEEE;
use IEEE.std_logic_1164.all;
use IEEE.numeric_std.all;

entity gcd is
  port(
    Ai, Bi : in unsigned(15 downto 0);
    init, clk : in std_logic;
    F : out unsigned(15 downto 0);
    fini : out std_logic
  );
end gcd;
  
architecture arch1 of gcd is
signal A, B, AmoinsB, BmoinsA : unsigned(15 downto 0);

begin
  AmoinsB <= A - B;
  BmoinsA <= B - A;
  F <= A;
  
  process(clk)
  begin
    if rising_edge(clk) then
      if init = '1' then
        A <= Ai;
        B <= Bi;
        fini <= '0';
      elsif A = B then
        fini <= '1';
      elsif AmoinsB(15) = '1' then -- A < B, mais gratuit.
        B <= BmoinsA;
        fini <= '0';
      else
        A <= AmoinsB;
        fini <= '0';
      end if;
    end if;
  end process;

end arch1;