arictl.vhd

基于fpga和sopc的用VHDL语言编写的EDA移位相加硬件乘法器

LIBRARY IEEE;
USE IEEE.STD_LOGIC_1164.ALL;
USE IEEE.STD_LOGIC_UNSIGNED.ALL;
ENTITY ARICTL IS
    PORT (CLK, START : IN STD_LOGIC;
        CLKOUT,RSTALL : OUT STD_LOGIC );
END ARICTL;
ARCHITECTURE behav OF ARICTL IS
    SIGNAL CNT4B : STD_LOGIC_VECTOR(3 DOWNTO 0);
BEGIN
    PROCESS(CLK, START)
    BEGIN
        RSTALL <= START;
        IF START = '1' THEN  CNT4B <= "0000";
        ELSIF CLK'EVENT AND CLK ='1' THEN
         IF CNT4B < 8 THEN CNT4B <= CNT4B + 1; END IF;
        END IF;
    END PROCESS;
    PROCESS(CLK, CNT4B, START)
    BEGIN
        IF START = '0' THEN
            IF CNT4B < 8 THEN  CLKOUT <= CLK;
            ELSE CLKOUT <= '0';  END IF;
        ELSE  CLKOUT <= CLK; END IF;
    END PROCESS;
END behav;