
--------------------------------------------------------------------------------
--
-- DIST MEM GEN Core - Checker
--
--------------------------------------------------------------------------------
--
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--------------------------------------------------------------------------------
--
-- Filename: stack_tb_checker.vhd
--
-- Description:
--   Checker
--
--------------------------------------------------------------------------------
-- Author: IP Solutions Division
--
-- History: Sep 12, 2011 - First Release
--------------------------------------------------------------------------------
--
--------------------------------------------------------------------------------
-- Library Declarations
--------------------------------------------------------------------------------

LIBRARY IEEE;
USE IEEE.STD_LOGIC_1164.ALL;
USE IEEE.STD_LOGIC_ARITH.ALL;
USE IEEE.STD_LOGIC_UNSIGNED.ALL;

LIBRARY work;
USE work.stack_TB_PKG.ALL;

ENTITY stack_TB_CHECKER IS
  GENERIC ( 
    WRITE_WIDTH : INTEGER :=32;
    READ_WIDTH  : INTEGER :=32
  );
        
  PORT (
    CLK      : IN STD_LOGIC;
    RST      : IN STD_LOGIC;
    EN       : IN STD_LOGIC; 
    DATA_IN  : IN STD_LOGIC_VECTOR (READ_WIDTH-1 DOWNTO 0);   --OUTPUT VECTOR          
    STATUS   : OUT STD_LOGIC:= '0'
  );
END stack_TB_CHECKER;

ARCHITECTURE CHECKER_ARCH OF stack_TB_CHECKER IS
  SIGNAL EXPECTED_DATA : STD_LOGIC_VECTOR(READ_WIDTH-1 DOWNTO 0);
  SIGNAL DATA_IN_R: STD_LOGIC_VECTOR(READ_WIDTH-1 DOWNTO 0);
  SIGNAL EN_R : STD_LOGIC := '0';
  SIGNAL EN_2R : STD_LOGIC := '0';
--DATA PART CNT DEFINES THE ASPECT RATIO AND GIVES THE INFO TO THE DATA GENERATOR TO PROVIDE THE DATA EITHER IN PARTS OR COMPLETE DATA IN ONE SHOT
--IF READ_WIDTH > WRITE_WIDTH DIVROUNDUP RESULTS IN '1' AND DATA GENERATOR GIVES THE DATAOUT EQUALS TO MAX OF (WRITE_WIDTH, READ_WIDTH)
--IF READ_WIDTH < WRITE-WIDTH DIVROUNDUP RESULTS IN > '1' AND DATA GENERATOR GIVES THE DATAOUT IN TERMS OF PARTS(EG 4 PARTS WHEN WRITE_WIDTH 32 AND READ WIDTH 8)
  CONSTANT DATA_PART_CNT: INTEGER:= DIVROUNDUP(WRITE_WIDTH,READ_WIDTH);
  CONSTANT MAX_WIDTH: INTEGER:= IF_THEN_ELSE((WRITE_WIDTH>READ_WIDTH),WRITE_WIDTH,READ_WIDTH);
  SIGNAL ERR_HOLD : STD_LOGIC :='0';
  SIGNAL ERR_DET : STD_LOGIC :='0';
BEGIN
  PROCESS(CLK)
  BEGIN
    IF(RISING_EDGE(CLK)) THEN
      IF(RST= '1') THEN
     	  EN_R <= '0';
     	  EN_2R <= '0';
        DATA_IN_R <= (OTHERS=>'0');
      ELSE
	     EN_R <= EN;
	     EN_2R <= EN_R;
        DATA_IN_R <= DATA_IN;
      END IF;        
    END IF;
  END PROCESS;

  EXPECTED_DGEN_INST:ENTITY work.stack_TB_DGEN 
    GENERIC MAP (
      DATA_GEN_WIDTH =>MAX_WIDTH,
      DOUT_WIDTH     => READ_WIDTH,
      DATA_PART_CNT  => DATA_PART_CNT,
      SEED           => 2
     )
     PORT MAP (
       CLK      => CLK,
  		 RST      => RST,
       EN       => EN_2R,
       DATA_OUT => EXPECTED_DATA
    );

  PROCESS(CLK)
  BEGIN
    IF(RISING_EDGE(CLK)) THEN
      IF(EN_2R='1') THEN
        IF(EXPECTED_DATA = DATA_IN_R) THEN
          ERR_DET<='0';
        ELSE
          ERR_DET<= '1';
        END IF;
      END IF;
    END IF;
  END PROCESS;

  PROCESS(CLK,RST)
  BEGIN
    IF(RST='1') THEN
  	   ERR_HOLD <= '0';
    ELSIF(RISING_EDGE(CLK)) THEN
      ERR_HOLD <= ERR_HOLD  OR ERR_DET ;
    END IF;
  END PROCESS;

  STATUS <= ERR_HOLD;

END ARCHITECTURE;

