--*******************************************************************--
-- Copyright (c) 1999-2000  Evatronix Ltd.                           --
--*******************************************************************--
-- Please review the terms of the license agreement before using     --
-- this file. If you are not an authorized user, please destroy this --
-- source code file and notify Evatronix S.A. immediately that you   --
-- inadvertently received an unauthorized copy.                      --
--*******************************************************************--

-----------------------------------------------------------------------
-- Project name         : C8051
-- Project description  : C8051 Microcontroller Unit
--
-- File name            : EXTSTIM.VHD
-- File contents        : Entity EXTERNAL_STIMULATOR
--                        Architecture SIM of EXTERNAL_STIMULATOR
-- Purpose              : Test vectors stimulator
--
-- Destination library  : C8051_LIB
-- Dependencies         : IEEE.STD_LOGIC_1164
--                        STD.TEXTIO
--
-- Design Engineer      : M.B.
-- Quality Engineer     : M.B.
-- Version              : 3.01
-- Last modification    : 2001-10-01
-----------------------------------------------------------------------

library IEEE;
   use IEEE.STD_LOGIC_1164.all;
   use STD.TEXTIO.ALL;


   entity EXTERNAL_STIMULATOR is
      generic (
              STIMFILE  : STRING  := "stim.txt";    -- Stimulus file
              FILEPATH  : STRING  := "tests/default"-- Path to the stim file
              );
      port (
           p0           : out STD_LOGIC_VECTOR (7 DOWNTO 0);
           p1           : out STD_LOGIC_VECTOR (7 DOWNTO 0);
           p2           : out STD_LOGIC_VECTOR (7 DOWNTO 0);
           p3           : out STD_LOGIC_VECTOR (7 DOWNTO 0);
           rst          : out STD_LOGIC;
           ea           : out STD_LOGIC
           );
   end EXTERNAL_STIMULATOR;



--*******************************************************************--

   architecture SIM of EXTERNAL_STIMULATOR is
   
   --------------------------------------------------------------------
   -- Converts CHARACTER to STD_LOGIC_VECTOR
   --------------------------------------------------------------------
      function TO_STD_LOGIC (char : CHARACTER) return STD_LOGIC is
         variable result : STD_LOGIC;
      begin
         case char is
            when 'U'|'u' => result := 'U';
            when '0'     => result := '0';
            when '1'     => result := '1';
            when 'X'|'x' => result := 'X';
            when 'L'|'l' => result := 'L';
            when 'H'|'h' => result := 'H';
            when 'W'|'w' => result := 'W';
            when 'Z'|'z' => result := 'Z';
            when '-'     => result := '-';
            when others  => result := 'X';
         end case;
         return result;
      end TO_STD_LOGIC;
   
   
   --------------------------------------------------------------------
   -- Converts STRING to STD_LOGIC_VECTOR
   --------------------------------------------------------------------
      function TO_STD_LOGIC_VECTOR (input : STRING) return STD_LOGIC_VECTOR is
         variable result : STD_LOGIC_VECTOR(input'range);
      begin
         for i in input'range loop
            result(i):=TO_STD_LOGIC(input(i));
         end loop;
         return result;
      end TO_STD_LOGIC_VECTOR;
   
   
   --------------------------------------------------------------------
   -- Reads vector of STD_LOGIC Characters from text line
   --------------------------------------------------------------------
      procedure READ (l : inout LINE; value : out STD_LOGIC_VECTOR) is
         variable char : CHARACTER;
      begin
         if l'length>0 then
            while l(l'left)=' ' loop
               READ(l,char);
            end loop;
            for i in value'range loop
               READ(l,char);
               value(i):=TO_STD_LOGIC(char);
            end loop;
         end if;
      end READ;
   
   
   --------------------------------------------------------------------
   -- Reads STD_LOGIC Character from text line
   --------------------------------------------------------------------
      procedure READ (l : inout LINE; value : out STD_LOGIC) is
         variable char : CHARACTER;
      begin
         if l'length>0 then
            while l(l'left)=' ' loop
               READ(l,char);
            end loop;
            READ(l,char);
            value:=TO_STD_LOGIC(char);
         end if;
      end READ;
   
   begin
   
   --------------------------------------------------------------------
   main :
   --------------------------------------------------------------------
      process
         file     stim  : TEXT is in FILEPATH & STIMFILE;
         variable l_in  : LINE;
         variable stop  : TIME;
         variable vp0   : STD_LOGIC_VECTOR(7 downto 0);
         variable vp1   : STD_LOGIC_VECTOR(7 downto 0);
         variable vp2   : STD_LOGIC_VECTOR(7 downto 0);
         variable vp3   : STD_LOGIC_VECTOR(7 downto 0);
         variable vrst  : STD_LOGIC;
         variable vea   : STD_LOGIC;
      begin
         ----------------------------------------
         -- Vectors stimulation
         ----------------------------------------
         while not ENDFILE(stim) loop
            READLINE(stim, l_in);
            if (l_in'length > 0) and (l_in(1)/='-') then
               READ(l_in, stop);
               READ(l_in, vp0);
               READ(l_in, vp1);
               READ(l_in, vp2);
               READ(l_in, vp3);
               READ(l_in, vrst);
               READ(l_in, vea);
               if NOW < stop then
                  wait for stop-NOW;
               end if;
               p0    <= vp0;
               p1    <= vp1;
               p2    <= vp2;
               p3    <= vp3;
               rst   <= vrst;
               ea    <= vea;
            end if;
         end loop;
         assert false
            report "End of the stimulus file detected."
            severity note;
         wait;
      end process;
   
   end SIM;

--*******************************************************************--