FOR LOOP using a Variable: 4-bit Left Shifter

Variable Declaration

Variable is initialized

LIBRARY ieee;

USE ieee.std_logic_1164.all;

USE ieee.std_logic_unsigned.all;

ENTITY shift4 IS

PORT ( shft_lft : in std_logic;

d_in : in std_logic_vector(3 downto 0);

q_out : out std_logic_vector(7 downto 0));

END shift4;

ARCHITECTURE logic OF shift4 IS

BEGIN

PROCESS(d_in, shft_lft)

VARIABLE shft_var : std_logic_vector(7 DOWNTO 0);

BEGIN

shft_var(7 downto 4) := "0000";

shft_var(3 downto 0) := d_in;