library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;

library work;
use work.common.all;
use work.glibc_random.all;
use work.ppc_fx_insns.all;

entity multiply_tb is
end multiply_tb;

architecture behave of multiply_tb is
	signal clk          : std_ulogic;
	constant clk_period : time := 10 ns;

	constant pipeline_depth: integer := 6;

	signal m1           : DecodeToMultiplyType;
	signal m2           : MultiplyToWritebackType;
begin
	multiply_0: entity work.multiply
		generic map (PIPELINE_DEPTH => pipeline_depth)
		port map (clk => clk, m_in => m1, m_out => m2);

	clk_process: process
	begin
		clk <= '0';
		wait for clk_period/2;
		clk <= '1';
		wait for clk_period/2;
	end process;

	stim_process: process
		variable ra, rb, rt, behave_rt: std_ulogic_vector(63 downto 0);
		variable si: std_ulogic_vector(15 downto 0);
	begin
		wait for clk_period;

		m1.valid <= '1';
		m1.mul_type <= LOWER_64;
		m1.nia <= (others => '0');
		m1.write_reg <= "10001";
		m1.data1 <= '0' & x"0000000000001000";
		m1.data2 <= '0' & x"0000000000001111";
		m1.rc <= '0';

		wait for clk_period;
		assert m2.valid = '0';

		m1.valid <= '0';

		wait for clk_period;
		assert m2.valid = '0';

		wait for clk_period;
		assert m2.valid = '0';

		wait for clk_period;
		assert m2.valid = '1';
		assert m2.write_enable = '1';
		assert m2.write_reg = "10001";
		assert m2.write_data = x"0000000001111000";
		assert m2.write_cr_enable = '0';

		wait for clk_period;
		assert m2.valid = '0';

		m1.valid <= '1';
		m1.rc <= '1';

		wait for clk_period;
		assert m2.valid = '0';

		m1.valid <= '0';

		wait for clk_period * (pipeline_depth-1);
		assert m2.valid = '1';
		assert m2.write_enable = '1';
		assert m2.write_reg = "10001";
		assert m2.write_data = x"0000000001111000";
		assert m2.write_cr_enable = '1';
		assert m2.cr = x"4";

		-- test mulld
		mulld_loop : for i in 0 to 1000 loop
			ra := pseudorand(ra'length);
			rb := pseudorand(rb'length);

			behave_rt := ppc_mulld(ra, rb);

			m1.data1 <= '0' & ra;
			m1.data2 <= '0' & rb;
			m1.valid <= '1';
			m1.mul_type <= LOWER_64;

			wait for clk_period;

			m1.valid <= '0';

			wait for clk_period * (pipeline_depth-1);

			assert m2.valid = '1';

			assert to_hstring(behave_rt) = to_hstring(m2.write_data)
				report "bad mulld expected " & to_hstring(behave_rt) & " got " & to_hstring(m2.write_data);
		end loop;

		-- test mulhdu
		mulhdu_loop : for i in 0 to 1000 loop
			ra := pseudorand(ra'length);
			rb := pseudorand(rb'length);

			behave_rt := ppc_mulhdu(ra, rb);

			m1.data1 <= '0' & ra;
			m1.data2 <= '0' & rb;
			m1.valid <= '1';
			m1.mul_type <= UPPER_64;

			wait for clk_period;

			m1.valid <= '0';

			wait for clk_period * (pipeline_depth-1);

			assert m2.valid = '1';

			assert to_hstring(behave_rt) = to_hstring(m2.write_data)
				report "bad mulhdu expected " & to_hstring(behave_rt) & " got " & to_hstring(m2.write_data);
		end loop;

		-- test mulhd
		mulhd_loop : for i in 0 to 1000 loop
			ra := pseudorand(ra'length);
			rb := pseudorand(rb'length);

			behave_rt := ppc_mulhd(ra, rb);

			m1.data1 <= ra(63) & ra;
			m1.data2 <= rb(63) & rb;
			m1.valid <= '1';
			m1.mul_type <= UPPER_64;

			wait for clk_period;

			m1.valid <= '0';

			wait for clk_period * (pipeline_depth-1);

			assert m2.valid = '1';

			assert to_hstring(behave_rt) = to_hstring(m2.write_data)
				report "bad mulhd expected " & to_hstring(behave_rt) & " got " & to_hstring(m2.write_data);
		end loop;

		-- test mullw
		mullw_loop : for i in 0 to 1000 loop
			ra := pseudorand(ra'length);
			rb := pseudorand(rb'length);

			behave_rt := ppc_mullw(ra, rb);

			m1.data1 <= (others => ra(31));
			m1.data1(31 downto 0) <= ra(31 downto 0);
			m1.data2 <= (others => rb(31));
			m1.data2(31 downto 0) <= rb(31 downto 0);
			m1.valid <= '1';
			m1.mul_type <= LOWER_64;

			wait for clk_period;

			m1.valid <= '0';

			wait for clk_period * (pipeline_depth-1);

			assert m2.valid = '1';

			assert to_hstring(behave_rt) = to_hstring(m2.write_data)
				report "bad mullw expected " & to_hstring(behave_rt) & " got " & to_hstring(m2.write_data);
		end loop;

		-- test mulhw
		mulhw_loop : for i in 0 to 1000 loop
			ra := pseudorand(ra'length);
			rb := pseudorand(rb'length);

			behave_rt := ppc_mulhw(ra, rb);

			m1.data1 <= (others => ra(31));
			m1.data1(31 downto 0) <= ra(31 downto 0);
			m1.data2 <= (others => rb(31));
			m1.data2(31 downto 0) <= rb(31 downto 0);
			m1.valid <= '1';
			m1.mul_type <= UPPER_32;

			wait for clk_period;

			m1.valid <= '0';

			wait for clk_period * (pipeline_depth-1);

			assert m2.valid = '1';

			assert to_hstring(behave_rt) = to_hstring(m2.write_data)
				report "bad mulhw expected " & to_hstring(behave_rt) & " got " & to_hstring(m2.write_data);
		end loop;

		-- test mulhwu
		mulhwu_loop : for i in 0 to 1000 loop
			ra := pseudorand(ra'length);
			rb := pseudorand(rb'length);

			behave_rt := ppc_mulhwu(ra, rb);

			m1.data1 <= (others => '0');
			m1.data1(31 downto 0) <= ra(31 downto 0);
			m1.data2 <= (others => '0');
			m1.data2(31 downto 0) <= rb(31 downto 0);
			m1.valid <= '1';
			m1.mul_type <= UPPER_32;

			wait for clk_period;

			m1.valid <= '0';

			wait for clk_period * (pipeline_depth-1);

			assert m2.valid = '1';

			assert to_hstring(behave_rt) = to_hstring(m2.write_data)
				report "bad mulhwu expected " & to_hstring(behave_rt) & " got " & to_hstring(m2.write_data);
		end loop;

		-- test mulli
		mulli_loop : for i in 0 to 1000 loop
			ra := pseudorand(ra'length);
			si := pseudorand(si'length);

			behave_rt := ppc_mulli(ra, si);

			m1.data1 <= ra(63) & ra;
			m1.data2 <= (others => si(15));
			m1.data2(15 downto 0) <= si;
			m1.valid <= '1';
			m1.mul_type <= LOWER_64;

			wait for clk_period;

			m1.valid <= '0';

			wait for clk_period * (pipeline_depth-1);

			assert m2.valid = '1';

			assert to_hstring(behave_rt) = to_hstring(m2.write_data)
				report "bad mulli expected " & to_hstring(behave_rt) & " got " & to_hstring(m2.write_data);
		end loop;

		assert false report "end of test" severity failure;
		wait;
	end process;
end behave;