computer/firmware/alu/tests/toy_16.vhd

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VHDL
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2018-02-15 19:23:44 +01:00
library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;
entity toy_16 is
end toy_16;
architecture test of toy_16 is
constant period: time := 1us;
component main
port (
func: in std_logic_vector(3 downto 0);
accu: in std_logic_vector(7 downto 0);
ram: in std_logic_vector(7 downto 0);
carry_in: in std_logic;
result: out std_logic_vector(7 downto 0);
carry_out: out std_logic
);
end component;
--Inputs
signal func: std_logic_vector(3 downto 0) := (others => '0');
signal accu: std_logic_vector(15 downto 0) := (others => '0');
signal ram: std_logic_vector(15 downto 0) := (others => '0');
signal carry_in: std_logic := '0';
--Outputs
signal result: std_logic_vector(15 downto 0);
signal carry_out: std_logic;
-- Internal signals
signal carry_propagation: std_logic;
-- Test constants
constant A: std_logic_vector(15 downto 0) := "1010101010101010";
constant B: std_logic_vector(15 downto 0) := "1100110011001100";
-- Info String (driven by procedure in test_process)
signal info_string: string(1 to 10);
begin
alu1: main port map (
func => func,
accu => accu(7 downto 0),
ram => ram(7 downto 0),
carry_in => '0',
result => result(7 downto 0),
carry_out => carry_propagation
);
alu2: main port map (
func => func,
accu => accu(15 downto 8),
ram => ram(15 downto 8),
carry_in => carry_propagation,
result => result(15 downto 8),
carry_out => open
);
test_process: process
procedure info(info: string) is
begin
info_string <= (others => ' ');
info_string(1 to info'length) <= info;
end procedure;
begin
--
-- logic tests
--
accu <= A; ram <= B; carry_in <= '0';
info("STORE");
func <= "0000";
wait for period;
assert result = A report "STORE failed";
info("LOAD");
func <= "0001";
wait for period;
assert result = B report "LOAD failed";
info("OR");
func <= "0101";
wait for period;
assert result = (A or B) report "OR failed";
info("AND");
func <= "0110";
wait for period;
assert result = (A and B) report "AND failed";
info("XOR");
func <= "0111";
wait for period;
assert result = (A xor B) report "XOR failed";
info("NOT");
func <= "1000";
wait for period;
assert result = not A report "NOT failed";
info("ZERO");
func <= "1011";
wait for period;
assert result = "0000000000000000" report "ZERO failed";
--
-- arithmatic tests
--
info("ADD");
accu <= "0100010011110011";
ram <= "0011100010101010"; carry_in <= '0';
func <= "0011";
wait for period;
assert result = "0111110110011101" report "ADD failed";
info("SUB");
accu <= "0100010000110011";
ram <= "0011100000101010"; carry_in <= '0';
func <= "0100";
wait for period;
assert result = "0000110000001001" report "SUB failed";
info("SUB-B");
accu <= "0100010010110011";
ram <= "0011100011101010"; carry_in <= '0';
func <= "0100";
wait for period;
assert result = "0000101111001001" report "SUB failed";
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info("INC");
accu <= "0000000000000000";
func <= "1001";
wait for period;
assert result = "0000000000000001" report "INC failed";
info("INC-O");
accu <= "1111111111111111";
func <= "1001";
wait for period;
assert result = "0000000000000000" report "INC-O failed";
info("DEC");
accu <= "0000000000000001";
func <= "1010";
wait for period;
assert result = "0000000000000000" report "DEC failed";
info("DEC-O");
accu <= "0000000000000000";
func <= "1010";
wait for period;
assert result = "1111111111111111" report "DEC-O failed";
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-- terminate test
wait;
end process;
end test;