From e8f3e33271cbfc1824e40294a4cd8a20c68b0974 Mon Sep 17 00:00:00 2001
From: Adrien Bourmault <neox@a-lec.org>
Date: Thu, 23 Dec 2021 17:35:49 +0100
Subject: [PATCH] Shifter_tb WIP

---
 shifter_tb.vhdl | 63 ++++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 57 insertions(+), 6 deletions(-)

diff --git a/shifter_tb.vhdl b/shifter_tb.vhdl
index fc43d87..ba3216b 100644
--- a/shifter_tb.vhdl
+++ b/shifter_tb.vhdl
@@ -19,6 +19,7 @@ signal  dout      :     Std_Logic_Vector(31 downto 0);
 signal  cout      :     Std_Logic;
 signal  vdd       :     bit := '1';
 signal  vss       :     bit := '0';
+
 begin
 
 shift: entity work.Shifter
@@ -37,13 +38,63 @@ port map(
             vss       => vss
          );
 process
+
+-- Variables for the random number
+variable seed1 : positive;
+variable seed2 : positive;
+variable x     : real;
+variable y     : integer;
+
+variable vdout : std_logic_vector(31 downto 0);
+variable vcout : std_logic;
+
 begin
-    shift_ror <= '1';
-    shift_val <= "00010";
-    din       <= std_logic_vector(to_unsigned(32654, 32));
-    wait for 5 ns;
-    report "dout = " & integer'image(to_integer(unsigned(dout)));
-    WAIT;
+    -- set vdd to 5v
+    vdd <= '1';
+    -- set vss to gnd
+    vss <= '0';
+
+    -- seeds for random number
+    seed1 := 1;
+    seed2 := 1;
+
+    wait for 1 ns;
+    report "[test_01] lsl with 32 random values";
+    shift_lsl <= '1';
+    la : for va in 0 to 31 loop
+
+      uniform(seed1, seed2, x);
+      y := integer(floor(x * 31.0)) + 1;
+
+      shift_val <= std_logic_vector(to_unsigned(y, shift_val'length));
+
+      uniform(seed1, seed2, x);
+      y := integer(floor(x * 536870911.0));
+      din <= std_logic_vector(to_unsigned(y, din'length));
+
+      if (y mod 2) = 0 then
+        cin <= '1';
+      else
+        cin <= '0';
+      end if;
+      wait for 1 ns;
+
+      --vdout := ?
+      --vcout := ?
+      
+      report "[test_01]: din = " & integer'image(to_integer(unsigned(din)));
+      report "[test_01]: shift_val = " & integer'image(to_integer(unsigned(shift_val)));
+
+      assert (dout = vdout) report "[error] lsl. vdout = " & integer'image(to_integer(unsigned(vdout))) & " versus dout = " & integer'image(to_integer(unsigned(dout))) severity error;
+      assert (cout = vcout) report "[error] lsl. vcout = " & integer'image(to_integer(unsigned(vcout))) & " versus cout = " & integer'image(to_integer(unsigned(cout))) severity error;
+      
+    end loop la;
+
+    report "[test_01] finished";
+    wait for 1 ns;
+    assert false report "end_of_test" severity note;
+    --  wait forever; this will finish the simulation.
+    wait;
 end process;
 
 end Structurel;