testsuite/synth: add a test for #1654

1 files changed, 86 insertions, 0 deletions

diff --git a/testsuite/synth/issue1654/tb_checker.vhdl b/testsuite/synth/issue1654/tb_checker.vhdl
new file mode 100644
index 000000000..f52e7ae8e
--- /dev/null
+++ b/testsuite/synth/issue1654/tb_checker.vhdl
@@ -0,0 +1,86 @@
+library ieee;
+  use ieee.std_logic_1164.all;
+
+
+entity sequencer is
+  generic (
+    seq : string
+  );
+  port (
+    clk  : in  std_logic;
+    data : out std_logic
+  );
+end entity sequencer;
+
+
+architecture rtl of sequencer is
+
+  signal index : natural := seq'low;
+
+  function to_bit (a : in character) return std_logic is
+    variable ret : std_logic;
+  begin
+    case a is
+      when '0' | '_' => ret := '0';
+      when '1' | '-' => ret := '1';
+      when others    => ret := 'X';
+    end case;
+    return ret;
+  end function to_bit;
+
+begin
+
+  process (clk) is
+  begin
+    if rising_edge(clk) then
+      if (index < seq'high) then
+        index <= index + 1;
+      end if;
+    end if;
+  end process;
+
+  data <= to_bit(seq(index));
+
+end architecture rtl;
+
+
+library ieee;
+  use ieee.std_logic_1164.all;
+
+use std.env.all;
+
+entity tb_checker is
+end;
+
+architecture sim of tb_checker is
+  signal clk   : std_logic := '1';
+  signal a, b, c, d : std_logic;
+begin
+  clk <= not clk after 500 ps;
+
+  -- async reset 100 ps after rising edge in cycle 1
+  d <= '0', '1' after 1100 ps, '0' after 1400 ps;
+
+  --                              0123456789
+  SEQ_A : entity work.sequencer generic map ("-___-_____") port map (clk, a);
+  SEQ_B : entity work.sequencer generic map ("_______-__") port map (clk, b);
+  SEQ_C : entity work.sequencer generic map ("-_________") port map (clk, c);
+  --  D :                                     _|________
+
+  dut: entity work.checker port map
+    (clk => clk, a => a, b => b, c => c, d => d);
+
+  -- stop simulation after 10 cycles
+  process
+    variable index : natural := 10;
+  begin
+    loop
+      wait until rising_edge(clk);
+      index := index - 1;
+      exit when index = 0;
+    end loop;
+    stop(0);
+  end process;
+
+
+end architecture sim;