countzero_tb.vhdl

   1 library ieee;
   2 use ieee.std_logic_1164.all;
   3 use ieee.numeric_std.all;
   4
   5 library work;
   6 use work.common.all;
   7 use work.glibc_random.all;
   8
   9 entity countzero_tb is
  10 end countzero_tb;
  11
  12 architecture behave of countzero_tb is
  13     constant clk_period: time := 10 ns;
  14     signal rs: std_ulogic_vector(63 downto 0);
  15     signal is_32bit, count_right: std_ulogic := '0';
  16     signal result: std_ulogic_vector(63 downto 0);
  17     signal randno: std_ulogic_vector(63 downto 0);
  18     signal clk: std_ulogic;
  19
  20 begin
  21     zerocounter_0: entity work.zero_counter
  22         port map (
  23             clk => clk,
  24             rs => rs,
  25             result => result,
  26             count_right => count_right,
  27             is_32bit => is_32bit
  28         );
  29
  30     clk_process: process
  31     begin
  32         clk <= '0';
  33         wait for clk_period/2;
  34         clk <= '1';
  35         wait for clk_period/2;
  36     end process;
  37
  38     stim_process: process
  39         variable r: std_ulogic_vector(63 downto 0);
  40     begin
  41         -- test with input = 0
  42         report "test zero input";
  43         rs <= (others => '0');
  44         is_32bit <= '0';
  45         count_right <= '0';
  46         wait for clk_period;
  47         assert result = x"0000000000000040"
  48             report "bad cntlzd 0 = " & to_hstring(result);
  49         count_right <= '1';
  50         wait for clk_period;
  51         assert result = x"0000000000000040"
  52             report "bad cnttzd 0 = " & to_hstring(result);
  53         is_32bit <= '1';
  54         count_right <= '0';
  55         wait for clk_period;
  56         assert result = x"0000000000000020"
  57             report "bad cntlzw 0 = " & to_hstring(result);
  58         count_right <= '1';
  59         wait for clk_period;
  60         assert result = x"0000000000000020"
  61             report "bad cnttzw 0 = " & to_hstring(result);
  62
  63         report "test cntlzd/w";
  64         count_right <= '0';
  65         for j in 0 to 100 loop
  66             r := pseudorand(64);
  67             r(63) := '1';
  68             for i in 0 to 63 loop
  69                 rs <= r;
  70                 is_32bit <= '0';
  71                 wait for clk_period;
  72                 assert to_integer(unsigned(result)) = i
  73                     report "bad cntlzd " & to_hstring(rs) & " -> " & to_hstring(result);
  74                 rs <= r(31 downto 0) & r(63 downto 32);
  75                 is_32bit <= '1';
  76                 wait for clk_period;
  77                 if i < 32 then
  78                     assert to_integer(unsigned(result)) = i
  79                         report "bad cntlzw " & to_hstring(rs) & " -> " & to_hstring(result);
  80                 else
  81                     assert to_integer(unsigned(result)) = 32
  82                         report "bad cntlzw " & to_hstring(rs) & " -> " & to_hstring(result);
  83                 end if;
  84                 r := '0' & r(63 downto 1);
  85             end loop;
  86         end loop;
  87
  88         report "test cnttzd/w";
  89         count_right <= '1';
  90         for j in 0 to 100 loop
  91             r := pseudorand(64);
  92             r(0) := '1';
  93             for i in 0 to 63 loop
  94                 rs <= r;
  95                 is_32bit <= '0';
  96                 wait for clk_period;
  97                 assert to_integer(unsigned(result)) = i
  98                     report "bad cnttzd " & to_hstring(rs) & " -> " & to_hstring(result);
  99                 is_32bit <= '1';
 100                 wait for clk_period;
 101                 if i < 32 then
 102                     assert to_integer(unsigned(result)) = i
 103                         report "bad cnttzw " & to_hstring(rs) & " -> " & to_hstring(result);
 104                 else
 105                     assert to_integer(unsigned(result)) = 32
 106                         report "bad cnttzw " & to_hstring(rs) & " -> " & to_hstring(result);
 107                 end if;
 108                 r := r(62 downto 0) & '0';
 109             end loop;
 110         end loop;
 111
 112         std.env.finish;
 113     end process;
 114 end behave;