-- THIS SOURCE CODE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
-- IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
-- OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
-- IN NO EVENT SHALL THE AUTHORT OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
-- INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
-- (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
--  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
-- AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
-- TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-- OF THIS CODE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.


library ieee;
use ieee.std_logic_1164.all;

entity gf_mul_1d is
	port(
		iA	: in std_logic_vector(7 downto 0);
		iB	: in std_logic_vector(7 downto 0);
		oC	: out std_logic_vector(7 downto 0)
	);
end entity;

architecture syn of gf_mul_1d is

signal a, b : std_logic_vector(7 downto 0);

signal d0, d1, d2, d3, d4, d5, d6, d7 : std_logic;
signal e0, e1, e2, e3, e4, e5, e6, e7 : std_logic;
signal c0, c1, c2, c3, c4, c5, c6, c7 : std_logic;


begin

a <= iA;
b <= iB;

d0 <= (a(0) and b(0));
d1 <= (a(1) and b(0)) xor (a(0) and b(1));
d2 <= (a(2) and b(0)) xor (a(1) and b(1)) xor (a(0) and b(2));
d3 <= (a(3) and b(0)) xor (a(2) and b(1)) xor (a(1) and b(2)) xor (a(0) and b(3));
d4 <= (a(4) and b(0)) xor (a(3) and b(1)) xor (a(2) and b(2)) xor (a(1) and b(3)) xor (a(0) and b(4));
d5 <= (a(5) and b(0)) xor (a(4) and b(1)) xor (a(3) and b(2)) xor (a(2) and b(3)) xor (a(1) and b(4)) xor (a(0) and b(5));
d6 <= (a(6) and b(0)) xor (a(5) and b(1)) xor (a(4) and b(2)) xor (a(3) and b(3)) xor (a(2) and b(4)) xor (a(1) and b(5)) xor (a(0) and b(6));
d7 <= (a(7) and b(0)) xor (a(6) and b(1)) xor (a(5) and b(2)) xor (a(4) and b(3)) xor (a(3) and b(4)) xor (a(2) and b(5)) xor (a(1) and b(6)) xor (a(0) and b(7));

e0 <= (a(7) and b(1)) xor (a(6) and b(2)) xor (a(5) and b(3)) xor (a(4) and b(4)) xor (a(3) and b(5)) xor (a(2) and b(6)) xor (a(1) and b(7));
e1 <= (a(7) and b(2)) xor (a(6) and b(3)) xor (a(5) and b(4)) xor (a(4) and b(5)) xor (a(3) and b(6)) xor (a(2) and b(7));
e2 <= (a(7) and b(3)) xor (a(6) and b(4)) xor (a(5) and b(5)) xor (a(4) and b(6)) xor (a(3) and b(7));
e3 <= (a(7) and b(4)) xor (a(6) and b(5)) xor (a(5) and b(6)) xor (a(4) and b(7));
e4 <= (a(7) and b(5)) xor (a(6) and b(6)) xor (a(5) and b(7));
e5 <= (a(7) and b(6)) xor (a(6) and b(7));
e6 <= (a(7) and b(7));

c0 <= d0 xor e0 xor e4 xor e5 xor e6;
c1 <= d1 xor e1 xor e5 xor e6;
c2 <= d2 xor e0 xor e2 xor e4 xor e5;
c3 <= d3 xor e0 xor e1 xor e3 xor e4;
c4 <= d4 xor e0 xor e1 xor e2 xor e6;
c5 <= d5 xor e1 xor e2 xor e3;
c6 <= d6 xor e2 xor e3 xor e4;
c7 <= d7 xor e3 xor e4 xor e5;

oC(0) <= c0;
oC(1) <= c1;
oC(2) <= c2;
oC(3) <= c3;
oC(4) <= c4;
oC(5) <= c5;
oC(6) <= c6;
oC(7) <= c7;

end syn;