key_pipeline3.vhd
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key_pipeline3.vhd
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			library ieee;
			use ieee.std_logic_1164.all;

			use ieee.numeric_std.all;
			use std.textio.all;
			use work.all;

			entity key_pipeline3 is
			port ( roundkeybit: out std_logic;
			Clk: in std_logic;
			init: in std_logic;
			swap_ctrl_k: in std_logic_vector(3 downto 0);
			lfsr_ctl3: in std_logic;
			KeyBit: in std_logic
			);
			end entity key_pipeline3;


			architecture behav of key_pipeline3 is

			signal k_p, k_n: std_logic_vector(127 downto 0);

			procedure rotate (
			variable s : inout std_logic_vector(127 downto 0);
			variable b: in std_logic
			) is
			begin
			s := s(126 downto 0) & b;
			end rotate;

			procedure swap (
			variable a: inout std_logic;
			variable b: inout std_logic
			) is
			variable tmp : std_logic;
			begin
			tmp := a;
			a := b;
			b := tmp;
			end swap;

			begin


			process (Clk)
			begin
			if Clk'event and Clk = '1' then
			k_p <= k_n;
			end if;
			end process;

			process (k_p, init, swap_ctrl_k, KeyBit, lfsr_ctl3)
			variable s : std_logic_vector(127 downto 0);
			variable nextbit: std_logic;
			variable tmp: std_logic_vector(7 downto 0);
			begin
			s := k_p;




			if swap_ctrl_k(0) = '1' then
			swap(s(127 - 56), s(127 - 120));
			end if;
			if swap_ctrl_k(1) = '1' then
			swap(s(127 - 48), s(127 - 56));
			end if;
			if swap_ctrl_k(2) = '1' then
			swap(s(127 - 24), s(127 - 56));
			end if;
			if swap_ctrl_k(3) = '1' then
			swap(s(127 - 24), s(127 - 8));
			end if;

			-- enable below for TK3
			if lfsr_ctl3 = '1' then
			s(120) := s(120) xor s(126);
			tmp := s(127 downto 120);
			s(126 downto 120) := tmp(7 downto 1);
			s(127) := tmp(0);
			end if;

			nextbit := s(127);
			if init = '1' then
			nextbit := KeyBit;
			end if;

			rotate(s, nextbit);



			roundkeybit <= s(8);
			k_n <= s;
			end process;

			end architecture;