You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
56 lines
1.8 KiB
56 lines
1.8 KiB
-- A testbench has no ports.
|
|
entity adder_tb is
|
|
end adder_tb;
|
|
|
|
architecture behav of adder_tb is
|
|
-- Declaration of the component that will be instantiated.
|
|
component adder
|
|
port (i0, i1 : in bit; ci : in bit; s : out bit; co : out bit);
|
|
end component;
|
|
-- Specifies which entity is bound with the component.
|
|
for adder_0: adder use entity work.adder;
|
|
signal i0, i1, ci, s, co : bit;
|
|
begin
|
|
-- Component instantiation.
|
|
adder_0: adder port map (i0 => i0, i1 => i1, ci => ci,
|
|
s => s, co => co);
|
|
|
|
-- This process does the real job.
|
|
process
|
|
type pattern_type is record
|
|
-- The inputs of the adder.
|
|
i0, i1, ci : bit;
|
|
-- The expected outputs of the adder.
|
|
s, co : bit;
|
|
end record;
|
|
-- The patterns to apply.
|
|
type pattern_array is array (natural range <>) of pattern_type;
|
|
constant patterns : pattern_array :=
|
|
(('0', '0', '0', '0', '0'),
|
|
('0', '0', '1', '1', '0'),
|
|
('0', '1', '0', '1', '0'),
|
|
('0', '1', '1', '0', '1'),
|
|
('1', '0', '0', '1', '0'),
|
|
('1', '0', '1', '0', '1'),
|
|
('1', '1', '0', '0', '1'),
|
|
('1', '1', '1', '1', '1'));
|
|
begin
|
|
-- Check each pattern.
|
|
for i in patterns'range loop
|
|
-- Set the inputs.
|
|
i0 <= patterns(i).i0;
|
|
i1 <= patterns(i).i1;
|
|
ci <= patterns(i).ci;
|
|
-- Wait for the results.
|
|
wait for 1 ns;
|
|
-- Check the outputs.
|
|
assert s = patterns(i).s
|
|
report "bad sum value" severity error;
|
|
assert co = patterns(i).co
|
|
report "bad carray out value" severity error;
|
|
end loop;
|
|
assert false report "end of test" severity note;
|
|
-- Wait forever; this will finish the simulation.
|
|
wait;
|
|
end process;
|
|
end behav;
|
|
|