multiplier.vhd

来自「在MAXPLUSII下实现BOOTH算法」· VHDL 代码 · 共 55 行

library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_unsigned.all;

entity multiplier is
	generic(k:positive:=8);		--input the number of multiplicand(or multiplier)
	port(
		M,multiplier:in std_logic_vector((k-1) downto 0);
		reset,clk:in std_logic;
		result:out std_logic_vector((2*k-1) downto 0);
		done:out std_logic);
end multiplier;

architecture behave of multiplier is
signal A,Q:std_logic_vector((k-1) downto 0);
signal count:integer range 0 to k;
signal step,qq:std_logic;


begin
process(clk)
	begin
	if reset='1' then
		A<=(others=>'0');
		qq<='0';
		Q<=multiplier;
		result<=(others=>'0');
		count<=k;
		step<='0';
		done<='0';
	elsif(clk'event and clk='1') then
		if(count/=0) then
			if step='0' then
				if Q(0)='1' and qq='0' then
					A<=A-M;
				elsif Q(0)='0' and qq='1' then
					A<=A+M;
				end if;
				step<='1';
			elsif step='1' then
				qq<=Q(0);
				Q<=A(0)&Q((k-1) downto 1);
				A((k-2) downto 0)<=A((k-1) downto 1);
				count<=count-1;
				step<='0';
			end if;
		else
			result<=A&Q;
			done<='1';
		end if;
	end if;
end process;
end behave;